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Gandhi G, Kodiappan R, Abdullah S, Teoh HK, Tai L, Cheong SK, Yeo WWY. Revealing the potential role of hsa-miR-663a in modulating the PI3K-Akt signaling pathway via miRNA microarray in spinal muscular atrophy patient fibroblast-derived iPSCs. J Neuropathol Exp Neurol 2024:nlae065. [PMID: 38894621 DOI: 10.1093/jnen/nlae065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2024] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder due to deletion or mutation of survival motor neuron 1 (SMN1) gene. Although survival motor neuron 2 (SMN2) gene is still present in SMA patients, the production of full-length survival motor neuron (SMN) protein is insufficient owing to missing or mutated SMN1. No current disease-modifying therapies can cure SMA. The aim of this study was to explore microRNA (miRNA)-based therapies that may serve as a potential target for therapeutic intervention in delaying SMA progression or as treatment. The study screened for potentially dysregulated miRNAs in SMA fibroblast-derived iPSCs using miRNA microarray. Results from the miRNA microarray were validated using quantitative reverse transcription polymerase chain reaction. Bioinformatics analysis using various databases was performed to predict the potential putative gene targeted by hsa-miR-663a. The findings showed differential expression of hsa-miR-663a in SMA patients in relation to a healthy control. Bioinformatics analysis identified GNG7, IGF2, and TNN genes that were targeted by hsa-miR-663a to be involved in the PI3K-AKT pathway, which may be associated with disease progression in SMA. Thus, this study suggests the potential role of hsa-miR-663a as therapeutic target for the treatment of SMA patients in the near future.
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Affiliation(s)
- Gayatri Gandhi
- Perdana University Graduate School of Medicine, Perdana University, Kuala Lumpur, Malaysia
| | - Radha Kodiappan
- Department of Research and Training, MAHSA Specialist Hospital, Selangor, Malaysia
| | - Syahril Abdullah
- Medical Genetics Laboratory, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
- Genetics & Regenerative Medicine Research Group, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, Selangor, Malaysia
- Malaysia Genome and Vaccine Institute, National Institutes of Biotechnology Malaysia, Selangor, Malaysia
| | - Hoon Koon Teoh
- Centre for Stem Cell Research, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Lihui Tai
- Centre for Stem Cell Research, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
- Cytopeutics Sdn. Bhd, Selangor, Malaysia
| | - Soon Keng Cheong
- Centre for Stem Cell Research, M. Kandiah Faculty of Medicine and Health Sciences, Universiti Tunku Abdul Rahman, Selangor, Malaysia
| | - Wendy Wai Yeng Yeo
- Perdana University Graduate School of Medicine, Perdana University, Kuala Lumpur, Malaysia
- School of Pharmacy, Monash University Malaysia, Selangor Darul Ehsan, Malaysia
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2
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Moakley DF, Campbell M, Anglada-Girotto M, Feng H, Califano A, Au E, Zhang C. Reverse engineering neuron type-specific and type-orthogonal splicing-regulatory networks using single-cell transcriptomes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.13.597128. [PMID: 38915499 PMCID: PMC11195221 DOI: 10.1101/2024.06.13.597128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/26/2024]
Abstract
Cell type-specific alternative splicing (AS) enables differential gene isoform expression between diverse neuron types with distinct identities and functions. Current studies linking individual RNA-binding proteins (RBPs) to AS in a few neuron types underscore the need for holistic modeling. Here, we use network reverse engineering to derive a map of the neuron type-specific AS regulatory landscape from 133 mouse neocortical cell types defined by single-cell transcriptomes. This approach reliably inferred the regulons of 350 RBPs and their cell type-specific activities. Our analysis revealed driving factors delineating neuronal identities, among which we validated Elavl2 as a key RBP for MGE-specific splicing in GABAergic interneurons using an in vitro ESC differentiation system. We also identified a module of exons and candidate regulators specific for long- and short-projection neurons across multiple neuronal classes. This study provides a resource for elucidating splicing regulatory programs that drive neuronal molecular diversity, including those that do not align with gene expression-based classifications.
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Simon CM, Delestree N, Montes J, Gerstner F, Carranza E, Sowoidnich L, Buettner JM, Pagiazitis JG, Prat-Ortega G, Ensel S, Donadio S, Garcia JL, Kratimenos P, Chung WK, Sumner CJ, Weimer LH, Pirondini E, Capogrosso M, Pellizzoni L, De Vivo DC, Mentis GZ. Dysfunction of proprioceptive sensory synapses is a pathogenic event and therapeutic target in mice and humans with spinal muscular atrophy. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.06.03.24308132. [PMID: 38883729 PMCID: PMC11177917 DOI: 10.1101/2024.06.03.24308132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2024]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by a varying degree of severity that correlates with the reduction of SMN protein levels. Motor neuron degeneration and skeletal muscle atrophy are hallmarks of SMA, but it is unknown whether other mechanisms contribute to the spectrum of clinical phenotypes. Here, through a combination of physiological and morphological studies in mouse models and SMA patients, we identify dysfunction and loss of proprioceptive sensory synapses as key signatures of SMA pathology. We demonstrate that SMA patients exhibit impaired proprioception, and their proprioceptive sensory synapses are dysfunctional as measured by the neurophysiological test of the Hoffmann reflex (H-reflex). We further show that loss of excitatory afferent synapses and altered potassium channel expression in SMA motor neurons are conserved pathogenic events found in both severely affected patients and mouse models. Lastly, we report that improved motor function and fatigability in ambulatory SMA patients and mouse models treated with SMN-inducing drugs correlate with increased function of sensory-motor circuits that can be accurately captured by the H-reflex assay. Thus, sensory synaptic dysfunction is a clinically relevant event in SMA, and the H-reflex is a suitable assay to monitor disease progression and treatment efficacy of motor circuit pathology.
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Affiliation(s)
- CM Simon
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - N Delestree
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
| | - J Montes
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Rehabilitation and Regenerative Medicine, Columbia University, NY, USA
| | - F Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - E Carranza
- Depts. Physical Medicine & Rehabilitation & Bioengineering, University of Pittsburgh, PA, USA
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
| | - L Sowoidnich
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - JM Buettner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig, Germany
| | - JG Pagiazitis
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
| | - G Prat-Ortega
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
- Depts. of Neurological Surgery & Bioengineering, University of Pittsburgh, PA, USA
| | - S Ensel
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
- Depts. of Neurological Surgery & Bioengineering, University of Pittsburgh, PA, USA
| | - S Donadio
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
- Depts. of Neurological Surgery & Bioengineering, University of Pittsburgh, PA, USA
| | - JL Garcia
- Dept. of Neurology, Columbia University, NY, USA
| | - P Kratimenos
- Center for Neuroscience Research, Children’s National Res. Institute, Washington, DC, USA
- Dept. of Pediatrics, G Washington Univ. Sch. of Medicine, Washington, DC, USA
| | - WK Chung
- Dept. of Pediatrics, Boston Children’s Hospital and Harvard Medical School, Boston, MA USA
| | - CJ Sumner
- Depts. of Neurology, Neuroscience and Genetic Medicine, Johns Hopkins University School of Medicine, MD, USA
| | - LH Weimer
- Dept. of Neurology, Columbia University, NY, USA
| | - E Pirondini
- Depts. Physical Medicine & Rehabilitation & Bioengineering, University of Pittsburgh, PA, USA
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
| | - M Capogrosso
- Rehab and Neural Engineering Labs, University of Pittsburgh, PA, USA
- Depts. of Neurological Surgery & Bioengineering, University of Pittsburgh, PA, USA
| | - L Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
- Dept. of Pathology and Cell Biology, Columbia University, NY, USA
| | - DC De Vivo
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
| | - GZ Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, NY, USA
- Dept. of Neurology, Columbia University, NY, USA
- Dept. of Pathology and Cell Biology, Columbia University, NY, USA
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Deng C, Chen H. Brain-derived neurotrophic factor/tropomyosin receptor kinase B signaling in spinal muscular atrophy and amyotrophic lateral sclerosis. Neurobiol Dis 2024; 190:106377. [PMID: 38092270 DOI: 10.1016/j.nbd.2023.106377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/15/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023] Open
Abstract
Tropomyosin receptor kinase B (TrkB) and its primary ligand brain-derived neurotrophic factor (BDNF) are expressed in the neuromuscular system, where they affect neuronal survival, differentiation, and functions. Changes in BDNF levels and full-length TrkB (TrkB-FL) signaling have been revealed in spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS), two common forms of motor neuron diseases that are characterized by defective neuromuscular junctions in early disease stages and subsequently progressive muscle weakness. This review summarizes the current understanding of BDNF/TrkB-FL-related research in SMA and ALS, with an emphasis on their alterations in the neuromuscular system and possible BDNF/TrkB-FL-targeting therapeutic strategies. The limitations of current studies and future directions are also discussed, giving the hope of discovering novel and effective treatments.
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Affiliation(s)
- Chunchu Deng
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hong Chen
- Department of Rehabilitation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
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Adam H, Gopinath SCB, Arshad MKM, Adam T, Subramaniam S, Hashim U. An Update on Parkinson's Disease and its Neurodegenerative Counterparts. Curr Med Chem 2024; 31:2770-2787. [PMID: 37016529 DOI: 10.2174/0929867330666230403085733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 01/26/2023] [Accepted: 02/10/2023] [Indexed: 04/06/2023]
Abstract
INTRODUCTION Neurodegenerative disorders are a group of diseases that cause nerve cell degeneration in the brain, resulting in a variety of symptoms and are not treatable with drugs. Parkinson's disease (PD), prion disease, motor neuron disease (MND), Huntington's disease (HD), spinal cerebral dyskinesia (SCA), spinal muscle atrophy (SMA), multiple system atrophy, Alzheimer's disease (AD), spinocerebellar ataxia (SCA) (ALS), pantothenate kinase-related neurodegeneration, and TDP-43 protein disorder are examples of neurodegenerative diseases. Dementia is caused by the loss of brain and spinal cord nerve cells in neurodegenerative diseases. BACKGROUND Even though environmental and genetic predispositions have also been involved in the process, redox metal abuse plays a crucial role in neurodegeneration since the preponderance of symptoms originates from abnormal metal metabolism. METHOD Hence, this review investigates several neurodegenerative diseases that may occur symptoms similar to Parkinson's disease to understand the differences and similarities between Parkinson's disease and other neurodegenerative disorders based on reviewing previously published papers. RESULTS Based on the findings, the aggregation of alpha-synuclein occurs in Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies. Other neurodegenerative diseases occur with different protein aggregation or mutations. CONCLUSION We can conclude that Parkinson's disease, Multiple system atrophy, and Dementia with Lewy bodies are closely related. Therefore, researchers must distinguish among the three diseases to avoid misdiagnosis of Multiple System Atrophy and Dementia with Lewy bodies with Parkinson's disease symptoms.
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Affiliation(s)
- Hussaini Adam
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
| | - Subash C B Gopinath
- Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), 02600, Arau, Perlis, Malaysia
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
- Micro System Technology, Centre of Excellence (CoE), Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600, Arau, Perlis, Malaysia
- Centre for Chemical Biology (CCB), Universiti Sains Malaysia, Bayan Lepas, 11900 Penang, Malaysia
| | - M K Md Arshad
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
- Faculty of Electronic Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600 Arau, Perlis, Malaysia
| | - Tijjani Adam
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
- Faculty of Electronic Engineering & Technology, Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600 Arau, Perlis, Malaysia
- Micro System Technology, Centre of Excellence (CoE), Universiti Malaysia Perlis (UniMAP), Pauh Campus, 02600, Arau, Perlis, Malaysia
| | - Sreeramanan Subramaniam
- School of Biological Sciences, Universiti Sains Malaysia, Georgetown, 11800 Penang, Malaysia
- Faculty of Chemical Engineering & Technology, Universiti Malaysia Perlis (UniMAP), 02600, Arau, Perlis, Malaysia
- Centre for Chemical Biology (CCB), Universiti Sains Malaysia, Bayan Lepas, 11900 Penang, Malaysia
- National Poison Centre, Universiti Sains Malaysia (USM), Georgetown, 11800, Penang, Malaysia
| | - Uda Hashim
- Institute of Nano Electronic Engineering, Universiti Malaysia Perlis (UniMAP), 01000, Kangar, Perlis, Malaysia
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Valsecchi V, Errico F, Bassareo V, Marino C, Nuzzo T, Brancaccio P, Laudati G, Casamassa A, Grimaldi M, D'Amico A, Carta M, Bertini E, Pignataro G, D'Ursi AM, Usiello A. SMN deficiency perturbs monoamine neurotransmitter metabolism in spinal muscular atrophy. Commun Biol 2023; 6:1155. [PMID: 37957344 PMCID: PMC10643621 DOI: 10.1038/s42003-023-05543-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 11/03/2023] [Indexed: 11/15/2023] Open
Abstract
Beyond motor neuron degeneration, homozygous mutations in the survival motor neuron 1 (SMN1) gene cause multiorgan and metabolic defects in patients with spinal muscular atrophy (SMA). However, the precise biochemical features of these alterations and the age of onset in the brain and peripheral organs remain unclear. Using untargeted NMR-based metabolomics in SMA mice, we identify cerebral and hepatic abnormalities related to energy homeostasis pathways and amino acid metabolism, emerging already at postnatal day 3 (P3) in the liver. Through HPLC, we find that SMN deficiency induces a drop in cerebral norepinephrine levels in overt symptomatic SMA mice at P11, affecting the mRNA and protein expression of key genes regulating monoamine metabolism, including aromatic L-amino acid decarboxylase (AADC), dopamine beta-hydroxylase (DβH) and monoamine oxidase A (MAO-A). In support of the translational value of our preclinical observations, we also discovered that SMN upregulation increases cerebrospinal fluid norepinephrine concentration in Nusinersen-treated SMA1 patients. Our findings highlight a previously unrecognized harmful influence of low SMN levels on the expression of critical enzymes involved in monoamine metabolism, suggesting that SMN-inducing therapies may modulate catecholamine neurotransmission. These results may also be relevant for setting therapeutic approaches to counteract peripheral metabolic defects in SMA.
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Affiliation(s)
- Valeria Valsecchi
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", 80131, Naples, Italy
| | - Francesco Errico
- Department of Agricultural Sciences, University of Naples "Federico II", 80055, Portici, Italy
- Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate, 80145, Naples, Italy
| | - Valentina Bassareo
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Carmen Marino
- Department of Pharmacy, University of Salerno, 84084, Fisciano, Salerno, Italy
| | - Tommaso Nuzzo
- Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate, 80145, Naples, Italy
- Department of Environmental, Biological and Pharmaceutical Science and Technologies, Università degli Studi della Campania "Luigi Vanvitelli", 81100, Caserta, Italy
| | - Paola Brancaccio
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", 80131, Naples, Italy
| | - Giusy Laudati
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", 80131, Naples, Italy
| | | | - Manuela Grimaldi
- Department of Pharmacy, University of Salerno, 84084, Fisciano, Salerno, Italy
| | - Adele D'Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital IRCCS, 00163, Rome, Italy
| | - Manolo Carta
- Department of Biomedical Sciences, University of Cagliari, 09042, Monserrato, Italy
| | - Enrico Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Bambino Gesù Children's Hospital IRCCS, 00163, Rome, Italy
| | - Giuseppe Pignataro
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", 80131, Naples, Italy
| | - Anna Maria D'Ursi
- Department of Pharmacy, University of Salerno, 84084, Fisciano, Salerno, Italy
| | - Alessandro Usiello
- Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate, 80145, Naples, Italy.
- Department of Environmental, Biological and Pharmaceutical Science and Technologies, Università degli Studi della Campania "Luigi Vanvitelli", 81100, Caserta, Italy.
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Delestrée N, Semizoglou E, Pagiazitis JG, Vukojicic A, Drobac E, Paushkin V, Mentis GZ. Serotonergic dysfunction impairs locomotor coordination in spinal muscular atrophy. Brain 2023; 146:4574-4593. [PMID: 37678880 PMCID: PMC10629775 DOI: 10.1093/brain/awad221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 05/12/2023] [Accepted: 06/11/2023] [Indexed: 09/09/2023] Open
Abstract
Neuromodulation by serotonin regulates the activity of neuronal networks responsible for a wide variety of essential behaviours. Serotonin (or 5-HT) typically activates metabotropic G protein-coupled receptors, which in turn initiate second messenger signalling cascades and induce short and long-lasting behavioural effects. Serotonin is intricately involved in the production of locomotor activity and gait control for different motor behaviours. Although dysfunction of serotonergic neurotransmission has been associated with mood disorders and spasticity after spinal cord injury, whether and to what extent such dysregulation is implicated in movement disorders has not been firmly established. Here, we investigated whether serotonergic neuromodulation is affected in spinal muscular atrophy (SMA), a neurodegenerative disease caused by ubiquitous deficiency of the SMN protein. The hallmarks of SMA are death of spinal motor neurons, muscle atrophy and impaired motor control, both in human patients and mouse models of disease. We used a severe mouse model of SMA, that closely recapitulates the severe symptoms exhibited by type I SMA patients, the most common and most severe form of the disease. Together, with mouse genetics, optogenetics, physiology, morphology and behavioural analysis, we report severe dysfunction of serotonergic neurotransmission in the spinal cord of SMA mice, both at early and late stages of the disease. This dysfunction is followed by reduction of 5-HT synapses on vulnerable motor neurons. We demonstrate that motor neurons innervating axial and trunk musculature are preferentially affected, suggesting a possible cause for the proximo-distal progression of disease, and raising the possibility that it may underlie scoliosis in SMA patients. We also demonstrate that the 5-HT dysfunction is caused by SMN deficiency in serotonergic neurons in the raphe nuclei of the brainstem. The behavioural significance of the dysfunction in serotonergic neuromodulation is underlined by inter-limb discoordination in SMA mice, which is ameliorated when selective restoration of SMN in 5-HT neurons is achieved by genetic means. Our study uncovers an unexpected dysfunction of serotonergic neuromodulation in SMA and indicates that, if normal function is to be restored under disease conditions, 5-HT neuromodulation should be a key target for therapeutic approaches.
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Affiliation(s)
- Nicolas Delestrée
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Evangelia Semizoglou
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - John G Pagiazitis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Aleksandra Vukojicic
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - Estelle Drobac
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Vasilissa Paushkin
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
| | - George Z Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA
- Department of Neurology, Columbia University, New York, NY 10032, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
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Qiao Y, Chi Y, Gu J, Ma Y. Safety and Efficacy of Nusinersen and Risdiplam for Spinal Muscular Atrophy: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Brain Sci 2023; 13:1419. [PMID: 37891788 PMCID: PMC10605531 DOI: 10.3390/brainsci13101419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 09/25/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
OBJECTIVE We performed a systematic review and meta-analysis of the efficacy and safety of nusinersen and risdiplam in the treatment of spinal muscular disease (SMA). METHODS We screened the literature published in Pubmed, Web of Science, Embase, and Cochrane before July 2023 to conduct randomized controlled trials to test the treatment of SMA patients with nusinersen and risdiplam. The data were analyzed using Review Manager 5.4 software and Stata version 15.0 software. RESULTS A total of six randomized controlled trials were included, involving 728 SMA patients, to synthesize evidence. It is reported that nusinersen treatment was beneficial for increasing the score of the Hammersmith Functional Motor Scale-Expanded (HFMSE) (WMD: 4.90; 95% CI: 3.17, 6.63; p < 0.00001), Revised Upper Limb Module (RULM) (WMD: 3.70; 95% CI: 3.30, 4.10; p < 0.00001), and Hammersmith Infant Neurological Evaluation Section 2 (HINE-2) (WMD: 5.21; 95% CI: 4.83, 5.60; p < 0.00001). In addition, the risdiplam treatment group also showed statistically significant improvements in the HFMSE score (WMD:0.87; 95% CI: 0.05, 1.68; p = 0.04), the 32-item Motor Function Measure (MFM32) (WMD:1.48; 95% CI: 0.58, 2.38; p = 0.001), and (WMD: 1.29; 95% CI: 0.57, 2.01; p = 0.0005). Nusinersen and risdiplam did not cause a statistically significant increase in the RULM score for adverse events (OR: 0.93; 95% CI: 0.51, 1.7; p = 0.82) and for severe adverse events (OR: 0.77; 95% CI: 0.47, 1.27; p = 0.31). CONCLUSION Our analysis found that nusinersen and risdiplam treatment showed clinically meaningful improvement in motor function and a similar incidence rate of adverse events compared with the placebo. Further research should be carried out to provide a direct comparison between the two drugs in terms of safety and efficacy.
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Affiliation(s)
| | | | | | - Ying Ma
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang 110055, China
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9
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Chand DH, Sun R, Diab KA, Kenny D, Tukov FF. Review of cardiac safety in onasemnogene abeparvovec gene replacement therapy: translation from preclinical to clinical findings. Gene Ther 2023; 30:685-697. [PMID: 37095320 PMCID: PMC10125853 DOI: 10.1038/s41434-023-00401-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 04/03/2023] [Accepted: 04/12/2023] [Indexed: 04/26/2023]
Abstract
Human gene replacement therapies such as onasemnogene abeparvovec (OA) use recombinant adeno-associated virus (rAAV) vectors to treat monogenic disorders. The heart and liver are known target organs of toxicity in animals; with cardiac and hepatic monitoring recommended in humans after OA dosing. This manuscript provides a comprehensive description of cardiac data from preclinical studies and clinical sources including clinical trials, managed access programs and the post-marketing setting following intravenous OA administration through 23 May 2022. Single dose mouse GLP-Toxicology studies revealed dose-dependent cardiac findings including thrombi, myocardial inflammation and degeneration/regeneration, which were associated with early mortality (4-7 weeks) in the high dose groups. No such findings were documented in non-human primates (NHP) after 6 weeks or 6 months post-dose. No electrocardiogram or echocardiogram abnormalities were noted in NHP or humans. After OA dosing, some patients developed isolated elevations in troponin without associated signs/symptoms; the reported cardiac adverse events in patients were considered of secondary etiology (e.g. respiratory dysfunction or sepsis leading to cardiac events). Clinical data indicate cardiac toxicity observed in mice does not translate to humans. Cardiac abnormalities have been associated with SMA. Healthcare professionals should use medical judgment when evaluating the etiology and assessment of cardiac events post OA dosing so as to consider all possibilities and manage the patient accordingly.
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Affiliation(s)
- Deepa H Chand
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA.
- Department of Pediatrics, University of Illinois College of Medicine and Children's Hospital of Illinois, Peoria, IL, USA.
| | - Rui Sun
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
| | - Karim A Diab
- Division of Cardiology, Department of Pediatrics, Inova Children's Hospital, Fairfax, VA, USA
| | - Damien Kenny
- Department of Paediatric Cardiology, CHI at Crumlin, Dublin, Ireland
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10
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Mucke HAM. Drug Repurposing Patent Applications April-June 2023. Assay Drug Dev Technol 2023; 21:288-295. [PMID: 37668595 DOI: 10.1089/adt.2023.081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2023] Open
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11
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Lumpkin CJ, Harris AW, Connell AJ, Kirk RW, Whiting JA, Saieva L, Pellizzoni L, Burghes AHM, Butchbach MER. Evaluation of the orally bioavailable 4-phenylbutyrate-tethered trichostatin A analogue AR42 in models of spinal muscular atrophy. Sci Rep 2023; 13:10374. [PMID: 37365234 PMCID: PMC10293174 DOI: 10.1038/s41598-023-37496-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 06/22/2023] [Indexed: 06/28/2023] Open
Abstract
Proximal spinal muscular atrophy (SMA) is a leading genetic cause for infant death in the world and results from the selective loss of motor neurons in the spinal cord. SMA is a consequence of low levels of SMN protein and small molecules that can increase SMN expression are of considerable interest as potential therapeutics. Previous studies have shown that both 4-phenylbutyrate (4PBA) and trichostatin A (TSA) increase SMN expression in dermal fibroblasts derived from SMA patients. AR42 is a 4PBA-tethered TSA derivative that is a very potent histone deacetylase inhibitor. SMA patient fibroblasts were treated with either AR42, AR19 (a related analogue), 4PBA, TSA or vehicle for 5 days and then immunostained for SMN localization. AR42 as well as 4PBA and TSA increased the number of SMN-positive nuclear gems in a dose-dependent manner while AR19 did not show marked changes in gem numbers. While gem number was increased in AR42-treated SMA fibroblasts, there were no significant changes in FL-SMN mRNA or SMN protein. The neuroprotective effect of this compound was then assessed in SMNΔ7 SMA (SMN2+/+;SMNΔ7+/+;mSmn-/-) mice. Oral administration of AR42 prior to disease onset increased the average lifespan of SMNΔ7 SMA mice by ~ 27% (20.1 ± 1.6 days for AR42-treated mice vs. 15.8 ± 0.4 days for vehicle-treated mice). AR42 treatment also improved motor function in these mice. AR42 treatment inhibited histone deacetylase (HDAC) activity in treated spinal cord although it did not affect SMN protein expression in these mice. AKT and GSK3β phosphorylation were both significantly increased in SMNΔ7 SMA mouse spinal cords. In conclusion, presymptomatic administration of the HDAC inhibitor AR42 ameliorates the disease phenotype in SMNΔ7 SMA mice in a SMN-independent manner possibly by increasing AKT neuroprotective signaling.
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Affiliation(s)
- Casey J Lumpkin
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
- Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Ashlee W Harris
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Andrew J Connell
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Ryan W Kirk
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Joshua A Whiting
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA
| | - Luciano Saieva
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Livio Pellizzoni
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
- Department of Neurology, Columbia University, New York, NY, USA
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Neurology, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Matthew E R Butchbach
- Division of Neurology, Nemours Children's Hospital Delaware, 4462 E400 DuPont Experimental Station, 200 Powder Mill Road, Wilmington, DE, 19803, USA.
- Department of Biological Sciences, University of Delaware, Newark, DE, USA.
- Department of Biological Chemistry and Pharmacology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA.
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12
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Szeto CH, Rubin S, Sidlow R. Homozygous EXOSC3 c.395A>C Variants in Pontocerebellar Hypoplasia Type 1B: A Sibling Pair With Childhood Lethal Presentation and Literature Review. Cureus 2023; 15:e39226. [PMID: 37337484 PMCID: PMC10277028 DOI: 10.7759/cureus.39226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2023] [Indexed: 06/21/2023] Open
Abstract
Pontocerebellar hypoplasia type 1B (PCH1B) is an autosomal recessive neurodegenerative disorder that involves hypoplasia or atrophy of the cerebellum and pons. PCH1B is caused by mutations in EXOSC3, which encodes a subunit of the RNA exosome complex. The most frequently observed mutation in PCH1B patients is a c.395A>C (p.D132A) missense variant, for which the homozygous mutation typically results in milder symptoms compared to compound heterozygous mutations or homozygous mutations for other pathogenic variants. In the present study, we report on a sibling pair harboring homozygous EXOSC3 c.395A>C missense variants who deteriorated more rapidly than previously described. These cases expand the spectrum of clinical manifestations of PCH1B associated with this variant, highlighting the need for further research to determine predictive factors of PCH1B severity.
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Affiliation(s)
- Chun Ho Szeto
- Medical School for International Health, Ben Gurion University of the Negev, Beer Sheva, ISR
| | - Sarina Rubin
- Medical School for International Health, Ben Gurion University of the Negev, Beer Sheva, ISR
| | - Richard Sidlow
- Medical Genetics and Metabolism, Valley Children's Hospital, Madera, USA
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13
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Riboldi GM, Faravelli I, Rinchetti P, Lotti F. SMN post-translational modifications in spinal muscular atrophy. Front Cell Neurosci 2023; 17:1092488. [PMID: 36874214 PMCID: PMC9981653 DOI: 10.3389/fncel.2023.1092488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/26/2023] [Indexed: 02/19/2023] Open
Abstract
Since its first identification as the gene responsible for spinal muscular atrophy (SMA), the range of survival motor neuron (SMN) protein functions has increasingly expanded. This multimeric complex plays a crucial role in a variety of RNA processing pathways. While its most characterized function is in the biogenesis of ribonucleoproteins, several studies have highlighted the SMN complex as an important contributor to mRNA trafficking and translation, axonal transport, endocytosis, and mitochondria metabolism. All these multiple functions need to be selectively and finely modulated to maintain cellular homeostasis. SMN has distinct functional domains that play a crucial role in complex stability, function, and subcellular distribution. Many different processes were reported as modulators of the SMN complex activities, although their contribution to SMN biology still needs to be elucidated. Recent evidence has identified post-translational modifications (PTMs) as a way to regulate the pleiotropic functions of the SMN complex. These modifications include phosphorylation, methylation, ubiquitination, acetylation, sumoylation, and many other types. PTMs can broaden the range of protein functions by binding chemical moieties to specific amino acids, thus modulating several cellular processes. Here, we provide an overview of the main PTMs involved in the regulation of the SMN complex with a major focus on the functions that have been linked to SMA pathogenesis.
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Affiliation(s)
| | | | | | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY, United States
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14
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Nuzzo T, Russo R, Errico F, D’Amico A, Tewelde AG, Valletta M, Hassan A, Tosi M, Panicucci C, Bruno C, Bertini E, Chambery A, Pellizzoni L, Usiello A. Nusinersen mitigates neuroinflammation in severe spinal muscular atrophy patients. COMMUNICATIONS MEDICINE 2023; 3:28. [PMID: 36792810 PMCID: PMC9932014 DOI: 10.1038/s43856-023-00256-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 02/02/2023] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Neuroinflammation contributes to the onset and progression of neurodegenerative diseases, but has not been specifically investigated in patients affected by severe and milder forms of spinal muscular atrophy (SMA). METHODS In this two-center retrospective study, we investigated signatures of neuroinflammation in forty-eight pediatric male and female SMA1 (n = 18), male and female SMA2 (n = 19), and female SMA3 (n = 11) patients, as well as in a limited number of male and female non-neurological control subjects (n = 4). We employed a Bio-Plex multiplex system based on xMAP technology and performed targeted quantitative analysis of a wide range of pro- and anti-inflammatory cytokines (chemokines, interferons, interleukins, lymphokines and tumor necrosis factors) and neurotrophic factors in the cerebrospinal fluid (CSF) of the study cohort before and after Nusinersen treatment at loading and maintenance stages. RESULTS We find a significant increase in the levels of several pro-inflammatory cytokines (IL-6, IFN-γ, TNF-α, IL-2, IL-8, IL-12, IL-17, MIP-1α, MCP-1, and Eotaxin) and neurotrophic factors (PDGF-BB and VEGF) in the CSF of SMA1 patients relative to SMA2 and SMA3 individuals, who display levels in the range of controls. We also find that treatment with Nusinersen significantly reduces the CSF levels of some but not all of these neuroinflammatory molecules in SMA1 patients. Conversely, Nusinersen increases the CSF levels of proinflammatory G-CSF, IL-8, MCP-1, MIP-1α, and MIP-1β in SMA2 patients and decreases those of anti-inflammatory IL-1ra in SMA3 patients. CONCLUSIONS These findings highlight signatures of neuroinflammation that are specifically associated with severe SMA and the neuro-immunomodulatory effects of Nusinersen therapy.
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Affiliation(s)
- Tommaso Nuzzo
- grid.9841.40000 0001 2200 8888Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy ,grid.511947.f0000 0004 1758 0953Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate Franco Salvatore, Naples, Italy
| | - Rosita Russo
- grid.9841.40000 0001 2200 8888Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy
| | - Francesco Errico
- grid.511947.f0000 0004 1758 0953Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate Franco Salvatore, Naples, Italy ,grid.4691.a0000 0001 0790 385XDepartment of Agricultural Sciences, University of Naples “Federico II”, Portici, Italy
| | - Adele D’Amico
- grid.414125.70000 0001 0727 6809Unit of Neuromuscular and Neurodegenerative Disorders, Dept. Neurosciences, Bambino Gesu’ Children’s Hospital IRCCS, Roma, Italy
| | - Awet G. Tewelde
- grid.9841.40000 0001 2200 8888Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy
| | - Mariangela Valletta
- grid.9841.40000 0001 2200 8888Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy
| | - Amber Hassan
- grid.511947.f0000 0004 1758 0953Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate Franco Salvatore, Naples, Italy
| | - Michele Tosi
- grid.414125.70000 0001 0727 6809Unit of Neuromuscular and Neurodegenerative Disorders, Dept. Neurosciences, Bambino Gesu’ Children’s Hospital IRCCS, Roma, Italy
| | - Chiara Panicucci
- grid.419504.d0000 0004 1760 0109Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Claudio Bruno
- grid.419504.d0000 0004 1760 0109Center of Translational and Experimental Myology, IRCCS Istituto Giannina Gaslini, Genoa, Italy ,grid.5606.50000 0001 2151 3065Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal, and Child Health - DINOGMI, University of Genoa, Genoa, Italy
| | - Enrico Bertini
- grid.414125.70000 0001 0727 6809Unit of Neuromuscular and Neurodegenerative Disorders, Dept. Neurosciences, Bambino Gesu’ Children’s Hospital IRCCS, Roma, Italy
| | - Angela Chambery
- grid.9841.40000 0001 2200 8888Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania “Luigi Vanvitelli”, Caserta, Italy
| | - Livio Pellizzoni
- grid.21729.3f0000000419368729Center for Motor Neuron Biology and Disease, Columbia University, New York, NY USA ,grid.21729.3f0000000419368729Department of Pathology and Cell Biology, Columbia University, New York, NY USA ,grid.21729.3f0000000419368729Department of Neurology, Columbia University, New York, NY USA
| | - Alessandro Usiello
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania "Luigi Vanvitelli", Caserta, Italy. .,Laboratory of Translational Neuroscience, Ceinge Biotecnologie Avanzate Franco Salvatore, Naples, Italy.
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15
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Faravelli I, Riboldi GM, Rinchetti P, Lotti F. The SMN Complex at the Crossroad between RNA Metabolism and Neurodegeneration. Int J Mol Sci 2023; 24:2247. [PMID: 36768569 PMCID: PMC9917330 DOI: 10.3390/ijms24032247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Revised: 01/17/2023] [Accepted: 01/20/2023] [Indexed: 01/24/2023] Open
Abstract
In the cell, RNA exists and functions in a complex with RNA binding proteins (RBPs) that regulate each step of the RNA life cycle from transcription to degradation. Central to this regulation is the role of several molecular chaperones that ensure the correct interactions between RNA and proteins, while aiding the biogenesis of large RNA-protein complexes (ribonucleoproteins or RNPs). Accurate formation of RNPs is fundamentally important to cellular development and function, and its impairment often leads to disease. The survival motor neuron (SMN) protein exemplifies this biological paradigm. SMN is part of a multi-protein complex essential for the biogenesis of various RNPs that function in RNA metabolism. Mutations leading to SMN deficiency cause the neurodegenerative disease spinal muscular atrophy (SMA). A fundamental question in SMA biology is how selective motor system dysfunction results from reduced levels of the ubiquitously expressed SMN protein. Recent clarification of the central role of the SMN complex in RNA metabolism and a thorough characterization of animal models of SMA have significantly advanced our knowledge of the molecular basis of the disease. Here we review the expanding role of SMN in the regulation of gene expression through its multiple functions in RNP biogenesis. We discuss developments in our understanding of SMN activity as a molecular chaperone of RNPs and how disruption of SMN-dependent RNA pathways can contribute to the SMA phenotype.
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Affiliation(s)
- Irene Faravelli
- Department of Stem Cell & Regenerative Biology, Harvard University, Cambridge, MA 02138, USA
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Giulietta M. Riboldi
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
- The Marlene and Paolo Fresco Institute for Parkinson’s and Movement Disorders, NYU Langone Health, New York, NY 10017, USA
| | - Paola Rinchetti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Francesco Lotti
- Center for Motor Neuron Biology and Diseases, Departments of Pathology & Cell Biology, and Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA
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16
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Hassan HA, Fahmy NA, El-Bagoury NM, Eissa NR, Sharaf-Eldin WE, Issa MY, Zaki MS, Essawi ML. MLPA analysis for molecular diagnosis of spinal muscular atrophy and correlation of 5q13.2 genes with disease phenotype in Egyptian patients. EGYPTIAN JOURNAL OF MEDICAL HUMAN GENETICS 2022. [DOI: 10.1186/s43042-022-00373-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Abstract
Background
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease representing the most prevalent monogenic cause of infant mortality. It results from the loss of SMN1 gene, but retention of its paralog SMN2 whose copy number can modulate the disease severity and guide the therapeutic regimen.
Methods
For SMA molecular analysis, 236 unrelated Egyptian patients were enrolled at our institution. The Multiplex ligation-dependent probe amplification analysis (MLPA) was applied to investigate the main genetic defect in the enrolled patients (SMN1 loss) and to determine a possible genotype–phenotype correlation between the copy number of other genes in the SMN locus (5q13.2) and disease severity in Egyptian patients with SMA. A small cohort of healthy subjects (n = 57) was also included to investigate the possible differences in the distributions of SMN2 and NAIP genes between patients and healthy individuals.
Results
Disease diagnosis was confirmed in only 148 patients (62.7%) highlighting the clinical overlapping of the disease and emphasizing the importance of molecular diagnosis. In patients with homozygous SMN1 loss, the disease was mediated by gene deletion and conversion in 135 (91.2%) and 13 (8.8%) patients, respectively. In the study cohort, SMN2 and NAIP copy numbers were inversely correlated with disease severity. However, no significant association was detected between GTF2H2A and SERF1B copy numbers and patient phenotype. Significant differences were demonstrated in the copy numbers of SMN2 and NAIP between SMA patients and healthy subjects.
Conclusion
Molecular analysis of SMA is essential for disease diagnosis. Consistent with previous studies on other populations, there is a close relationship between SMN2 and NAIP copy numbers and clinical phenotype. Additionally, potential differences in these two genes distributions are existing between patients and healthy subjects. National program for carrier screening should be established as a preventive disease strategy. On the other hand, neonatal testing would provide accurate estimation for disease incidence.
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17
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Buettner JM, Sowoidnich L, Gerstner F, Blanco-Redondo B, Hallermann S, Simon CM. p53-dependent c-Fos expression is a marker but not executor for motor neuron death in spinal muscular atrophy mouse models. Front Cell Neurosci 2022; 16:1038276. [DOI: 10.3389/fncel.2022.1038276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/18/2022] [Indexed: 11/09/2022] Open
Abstract
The activation of the p53 pathway has been associated with neuronal degeneration in different neurological disorders, including spinal muscular atrophy (SMA) where aberrant expression of p53 drives selective death of motor neurons destined to degenerate. Since direct p53 inhibition is an unsound therapeutic approach due carcinogenic effects, we investigated the expression of the cell death-associated p53 downstream targets c-fos, perp and fas in vulnerable motor neurons of SMA mice. Fluorescence in situ hybridization (FISH) of SMA motor neurons revealed c-fos RNA as a promising candidate. Accordingly, we identified p53-dependent nuclear upregulation of c-Fos protein in degenerating motor neurons from the severe SMNΔ7 and intermediate Smn2B/– SMA mouse models. Although motor neuron-specific c-fos genetic deletion in SMA mice did not improve motor neuron survival or motor behavior, p53-dependent c-Fos upregulation marks vulnerable motor neurons in different mouse models. Thus, nuclear c-Fos accumulation may serve as a readout for therapeutic approaches targeting neuronal death in SMA and possibly other p53-dependent neurodegenerative diseases.
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18
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Gowda VL, Fernandez-Garcia MA, Jungbluth H, Wraige E. New treatments in spinal muscular atrophy. Arch Dis Child 2022:archdischild-2021-323605. [PMID: 36316089 DOI: 10.1136/archdischild-2021-323605] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 10/13/2022] [Indexed: 11/04/2022]
Abstract
Spinal muscular atrophy (SMA) is a severe neurodegenerative condition due to recessive mutations in the SMN1 gene resulting in insufficiency of survival motor neuron (SMN) protein. Lack of SMN protein results in irreversible degeneration of lower motor neurons and consequential muscle atrophy and weakness. SMN2, a SMN1 homologue, produces low levels of functional SMN protein with the potential to partially compensate SMN1 loss. Several compounds have been shown to successfully restore SMN protein production in motor neurons, either by enhancing SMN2 gene function or by direct replacement of the SMN1 gene. Clinical trials of these compounds have demonstrated the potential to substantially alter the natural history of SMA and have led to their implementation into clinical practice. To date, 3 novel drugs, nusinersen, onasemnogene aberparvovec and risdiplam, have received marketing authorisation for SMA treatment by several authorities including Food and Drug Administration and European Medicines Agency. While implementing these drugs into daily clinical practice, clinicians face a number of new challenges, including identifying the most advantageous treatment for any individual, optimisation of outcomes and management of a modified SMA phenotype. Considering that treatment initiation at the pre-symptomatic or paucisymptomatic stage appears to be associated with better outcomes, health services need to support early diagnosis for this now treatable condition. This review aims to give an overview of the current therapeutic landscape of SMA, to provide an understanding of current practice of SMA management and to help increase awareness of the imminent need for urgent early diagnosis at the pre-symptomatic stage.
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Affiliation(s)
| | | | - Heinz Jungbluth
- Department of Paediatric Neurology, Evelina London Children's Hospital, London, UK.,Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine, King's College London, London, UK
| | - Elizabeth Wraige
- Department of Paediatric Neurology, Evelina London Children's Hospital, London, UK
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19
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SMN controls neuromuscular junction integrity through U7 snRNP. Cell Rep 2022; 40:111393. [PMID: 36130491 PMCID: PMC9533342 DOI: 10.1016/j.celrep.2022.111393] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/18/2022] [Accepted: 08/30/2022] [Indexed: 01/26/2023] Open
Abstract
The neuromuscular junction (NMJ) is an essential synapse whose loss is a key hallmark of the neurodegenerative disease spinal muscular atrophy (SMA). Here, we show that activity of the SMA-determining SMN protein in the assembly of U7 small nuclear ribonucleoprotein (snRNP)—which functions in the 3′-end processing of replication-dependent histone mRNAs—is required for NMJ integrity. Co-expression of U7-specific Lsm10 and Lsm11 proteins selectively enhances U7 snRNP assembly, corrects histone mRNA processing defects, and rescues key structural and functional abnormalities of neuromuscular pathology in SMA mice—including NMJ denervation, decreased synaptic transmission, and skeletal muscle atrophy. Furthermore, U7 snRNP dysfunction drives selective loss of the synaptic organizing protein Agrin at NMJs innervating vulnerable muscles of SMA mice. These findings reveal a direct contribution of U7 snRNP dysfunction to neuromuscular pathology in SMA and suggest a role for histone gene regulation in maintaining functional synaptic connections between motor neurons and muscles. NMJ denervation is a hallmark of SMA. Through selective restoration of U7 snRNP biogenesis in SMA mice, Tisdale et al. reveal a role for SMN-mediated U7 snRNP assembly and histone mRNA processing in controlling NMJ integrity through Agrin expression, uncovering RNA-mediated disease mechanisms and linking U7 function to neuromuscular development.
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20
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Chen L, Roake CM, Maccallini P, Bavasso F, Dehghannasiri R, Santonicola P, Mendoza-Ferreira N, Scatolini L, Rizzuti L, Esposito A, Gallotta I, Francia S, Cacchione S, Galati A, Palumbo V, Kobin MA, Tartaglia G, Colantoni A, Proietti G, Wu Y, Hammerschmidt M, De Pittà C, Sales G, Salzman J, Pellizzoni L, Wirth B, Di Schiavi E, Gatti M, Artandi S, Raffa GD. TGS1 impacts snRNA 3'-end processing, ameliorates survival motor neuron-dependent neurological phenotypes in vivo and prevents neurodegeneration. Nucleic Acids Res 2022; 50:12400-12424. [PMID: 35947650 PMCID: PMC9757054 DOI: 10.1093/nar/gkac659] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 07/21/2022] [Indexed: 12/24/2022] Open
Abstract
Trimethylguanosine synthase 1 (TGS1) is a highly conserved enzyme that converts the 5'-monomethylguanosine cap of small nuclear RNAs (snRNAs) to a trimethylguanosine cap. Here, we show that loss of TGS1 in Caenorhabditis elegans, Drosophila melanogaster and Danio rerio results in neurological phenotypes similar to those caused by survival motor neuron (SMN) deficiency. Importantly, expression of human TGS1 ameliorates the SMN-dependent neurological phenotypes in both flies and worms, revealing that TGS1 can partly counteract the effects of SMN deficiency. TGS1 loss in HeLa cells leads to the accumulation of immature U2 and U4atac snRNAs with long 3' tails that are often uridylated. snRNAs with defective 3' terminations also accumulate in Drosophila Tgs1 mutants. Consistent with defective snRNA maturation, TGS1 and SMN mutant cells also exhibit partially overlapping transcriptome alterations that include aberrantly spliced and readthrough transcripts. Together, these results identify a neuroprotective function for TGS1 and reinforce the view that defective snRNA maturation affects neuronal viability and function.
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Affiliation(s)
- Lu Chen
- Correspondence may also be addressed to Lu Chen.
| | | | - Paolo Maccallini
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Francesca Bavasso
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Roozbeh Dehghannasiri
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA,Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
| | | | - Natalia Mendoza-Ferreira
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, 50931 Cologne, Germany
| | - Livia Scatolini
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Ludovico Rizzuti
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | | | - Ivan Gallotta
- Institute of Genetics and Biophysics, IGB-ABT, CNR, Naples, Italy
| | - Sofia Francia
- IFOM-The FIRC Institute of Molecular Oncology, Milan, Italy,Istituto di Genetica Molecolare, CNR-Consiglio Nazionale delle Ricerche, Pavia, Italy
| | - Stefano Cacchione
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Alessandra Galati
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Valeria Palumbo
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy
| | - Marie A Kobin
- Cancer Signaling and Epigenetics Program and Cancer Epigenetics Institute, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Gian Gaetano Tartaglia
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy,Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy,Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Alessio Colantoni
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy,Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy,Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Gabriele Proietti
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), Rome 00161, Italy,Center for Human Technology, Fondazione Istituto Italiano di Tecnologia (IIT), Genoa 16152, Italy
| | - Yunming Wu
- Cancer Signaling and Epigenetics Program and Cancer Epigenetics Institute, Institute for Cancer Research, Fox Chase Cancer Center, Philadelphia, PA 19111, USA,Department of Biology, Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
| | - Matthias Hammerschmidt
- Institute for Zoology, Developmental Biology, University of Cologne, 50674 Cologne, Germany
| | | | - Gabriele Sales
- Department of Biology, University of Padova, Padua, Italy
| | - Julia Salzman
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA,Department of Biomedical Data Science, Stanford University, Stanford, CA 94305, USA
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, NY 10032, USA,Department of Pathology and Cell Biology, Columbia University, NY 10032, USA,Department of Neurology, Columbia University, NY 10032, USA
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, 50931 Cologne, Germany,Center for Rare Diseases, University Hospital of Cologne, University of Cologne, 50931 Cologne, Germany
| | - Elia Di Schiavi
- Institute of Biosciences and BioResources, IBBR, CNR, Naples, Italy,Institute of Genetics and Biophysics, IGB-ABT, CNR, Naples, Italy
| | - Maurizio Gatti
- Dipartimento di Biologia e Biotecnologie, Sapienza University of Rome, Rome, Italy,Istituto di Biologia e Patologia Molecolari (IBPM) del CNR, Rome, Italy
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21
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Carlini MJ, Triplett MK, Pellizzoni L. Neuromuscular denervation and deafferentation but not motor neuron death are disease features in the Smn2B/- mouse model of SMA. PLoS One 2022; 17:e0267990. [PMID: 35913953 PMCID: PMC9342749 DOI: 10.1371/journal.pone.0267990] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 07/13/2022] [Indexed: 12/02/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease characterized by loss of motor neurons and skeletal muscle atrophy which is caused by ubiquitous deficiency in the survival motor neuron (SMN) protein. Several cellular defects contribute to sensory-motor circuit pathology in SMA mice, but the underlying mechanisms have often been studied in one mouse model without validation in other available models. Here, we used Smn2B/- mice to investigate specific behavioral, morphological, and functional aspects of SMA pathology that we previously characterized in the SMNΔ7 model. Smn2B/- SMA mice on a pure FVB/N background display deficits in body weight gain and muscle strength with onset in the second postnatal week and median survival of 19 days. Morphological analysis revealed severe loss of proprioceptive synapses on the soma of motor neurons and prominent denervation of neuromuscular junctions (NMJs) in axial but not distal muscles. In contrast, no evidence of cell death emerged from analysis of several distinct pools of lumbar motor neurons known to be lost in the disease. Moreover, SMA motor neurons from Smn2B/- mice showed robust nuclear accumulation of p53 but lack of phosphorylation of serine 18 at its amino-terminal, which selectively marks degenerating motor neurons in the SMNΔ7 mouse model. These results indicate that NMJ denervation and deafferentation, but not motor neuron death, are conserved features of SMA pathology in Smn2B/- mice.
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Affiliation(s)
- Maria J. Carlini
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
| | - Marina K. Triplett
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, United States of America
- Department of Neurology, Columbia University, New York, NY, United States of America
- Department of Pathology and Cell Biology, Columbia University, New York, NY, United States of America
- * E-mail:
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22
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Kanda S, Moulton E, Butchbach MER. Effects of inhibitors of SLC9A-type sodium-protein exchangers on Survival Motor Neuron 2 ( SMN2) mRNA splicing and expression. Mol Pharmacol 2022; 102:92-105. [PMID: 35667685 PMCID: PMC9341265 DOI: 10.1124/molpharm.122.000529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/09/2022] [Indexed: 11/22/2022] Open
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive, pediatric-onset disorder caused by the loss of spinal motor neurons thereby leading to muscle atrophy. SMA is caused by the loss of or mutations in the survival motor neuron 1 (SMN1) gene. SMN1 is duplicated in humans to give rise to the paralogous SMN2 gene. This paralog is nearly identical except for a cytosine to thymine (C-to-T) transition within an exonic splicing enhancer (ESE) element within exon 7. As a result, the majority of SMN2 transcripts lack exon 7 (SMNΔ7) which produces a truncated and unstable SMN protein. Since SMN2 copy number is inversely related to disease severity, it is a well-established target for SMA therapeutics development. 5-(N-ethyl-N-isopropyl)amiloride (EIPA), an inhibitor of sodium/proton exchangers (NHEs), has previously been shown to increase exon 7 inclusion and SMN protein levels in SMA cells. In this study, NHE inhibitors were evaluated for their ability to modulate SMN2 expression. EIPA as well as 5-(N,N-hexamethylene)amiloride (HMA) increase exon 7 inclusion in SMN2 splicing reporter lines as well as in SMA fibroblasts. The EIPA-induced exon 7 inclusion occurs via a unique mechanism that does not involve previously identified splicing factors. Transcriptome analysis identified novel targets, including TIA1 and FABP3, for further characterization. EIPA and HMA are more selective at inhibiting the NHE5 isoform, which is expressed in fibroblasts as well as in neuronal cells. These results show that NHE5 inhibition increases SMN2 expression and may be a novel target for therapeutics development. Significance Statement This study demonstrates a molecular mechanism by which inhibitors of the sodium-protein exchanger increase the alternative splicing of SMN2 in spinal muscular atrophy cells. NHE5 selective inhibitors increase the inclusion of full-length SMN2 mRNAs by targeting TIA1 and FABP3 expression, which is distinct from other small molecule regulators of SMN2 alternative splicing. This study provides a novel means to increase full-length SMN2 expression and a novel target for therapeutics development.
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Affiliation(s)
- Sambee Kanda
- Biological Sciences, University of Delaware, United States
| | - Emily Moulton
- Biomedical Research, Nemours Children's Hospital Delaware, United States
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23
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Yang M, Awano H, Tanaka S, Toro W, Zhang S, Dabbous O, Igarashi A. Systematic Literature Review of Clinical and Economic Evidence for Spinal Muscular Atrophy. Adv Ther 2022; 39:1915-1958. [PMID: 35307799 PMCID: PMC9056474 DOI: 10.1007/s12325-022-02089-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/15/2022] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The recent advent of disease-modifying therapies (DMTs) has dramatically changed the treatment landscape of spinal muscular atrophy (SMA), and the multifaceted impact of this advancement has not been assessed thoroughly in the growing body of literature. We sought to summarize the literature on the natural history of SMA and the impact of SMA DMTs, including health-related quality of life (HRQOL) and utilities, clinical efficacy and safety, and economic impact. METHODS Systematic literature reviews were conducted following PRISMA guidelines with no inclusive dates. Relevant studies were identified by searching full-text databases on November 12-13, 2020, including MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, and EconLit, conference proceedings, health technology assessment databases, and clinical trial registries. All searches used a combination of MeSH and key terms. Studies were screened according to criteria based upon population, intervention, outcomes, and study design structure. RESULTS Findings from 17, 23, 32, and 42 studies were included for the evaluation of natural history of SMA, HRQOL and utilities, clinical efficacy and safety, and economic impact of DMTs, respectively. Currently available data indicate that untreated SMA is associated with considerable humanistic and economic burden, with estimates of costs varying by treatment. While a variety of interventions have been evaluated in SMA clinical trials, quantitative synthesis of safety and efficacy findings was not feasible because of inconsistencies in reported outcomes. Data assessing impacts of DMTs on HRQOL were also lacking. CONCLUSIONS Overall, this systematic literature review highlights a clear need for up-to-date and methodologically rigorous clinical, HRQOL, and economic data to support unbiased assessments of the relative clinical and economic effectiveness of SMA treatments. More research is required to extend our understanding of the burden of SMA on HRQOL utility assessments and the impact of new DMTs on HRQOL and utilities for patients with SMA.
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Affiliation(s)
- Min Yang
- Analysis Group, Inc., 111 Huntington Avenue, Fourteenth Floor, Boston, MA, 02199, USA.
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | - Walter Toro
- Novartis Gene Therapies, Inc., Bannockburn, IL, USA
| | - Su Zhang
- Analysis Group, Inc., 111 Huntington Avenue, Fourteenth Floor, Boston, MA, 02199, USA
| | - Omar Dabbous
- Novartis Gene Therapies, Inc., Bannockburn, IL, USA
| | - Ataru Igarashi
- Unit of Public Health and Preventive Medicine, Yokohama City University, Yokohama, Japan
- Department of Health Economics and Outcomes Research, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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24
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Markati T, Fisher G, Ramdas S, Servais L. Risdiplam: an investigational motor neuron-2 (SMN-2) splicing modifier for spinal muscular atrophy (SMA). Expert Opin Investig Drugs 2022; 31:451-461. [PMID: 35316106 DOI: 10.1080/13543784.2022.2056836] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disease which is characterized by muscle atrophy and early death in most patients. Risdiplam is the third overall and first oral drug approved for SMA with disease-modifying potential. Risdiplam acts as a survival motor neuron 2 (SMN2) pre-mRNA splicing modifier with satisfactory safety and efficacy profile. This review aims to critically appraise the place of risdiplam in the map of SMA therapeutics. AREAS COVERED This review gives an overview of the current market for SMA and presents the mechanism of action and the pharmacological properties of risdiplam. It also outlines the development of risdiplam from early preclinical stages through to the most recently published results from phase 2/3 clinical trials. Risdiplam has proved its efficacy in pivotal trials for SMA Types 1, 2, and 3 with a satisfactory safety profile. EXPERT OPINION In the absence of comparative data with the other two approved drugs, the role of risdiplam in the treatment algorithm of affected individuals is examined in three different patient populations based on the age and diagnosis method (newborn screening or clinical, symptom-driven diagnosis). Long-term data and real-world data will play a fundamental role in its future.
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Affiliation(s)
- Theodora Markati
- MDUK Oxford Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Gemma Fisher
- MDUK Oxford Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Sithara Ramdas
- MDUK Oxford Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Laurent Servais
- MDUK Oxford Neuromuscular Center, Department of Paediatrics, University of Oxford, Oxford, UK.,Oxford University Hospitals NHS Foundation Trust, Oxford, UK.,Division of Child Neurology, Centre de Références des Maladies Neuromusculaires, Department of Pediatrics, University Hospital Liège & University of Liège, Belgium
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25
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Chalif JI, Mentis GZ. Normal Development and Pathology of Motoneurons: Anatomy, Electrophysiological Properties, Firing Patterns and Circuit Connectivity. ADVANCES IN NEUROBIOLOGY 2022; 28:63-85. [PMID: 36066821 DOI: 10.1007/978-3-031-07167-6_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
This chapter will provide an introduction into motoneuron anatomy, electrophysiological properties, firing patterns focusing on development and also describing several pathological conditions that affect mononeurons. It starts with a historical retrospective describing the early landmark work into motoneurons. The next section lays out the various types of motoneurons (alpha, beta, and gamma) and their subclasses (fast-twitch fatigable, fast-twitch fatigue-resistant, and slow-twitch fatigue resistant), highlighting the functional relevance of this classification scheme. The third section describes the development of motoneurons' passive and active electrophysiological properties. This section also defines the major terms one uses in describing how a neuron functions electrophysiologically. The electrophysiological aspects of a neuron is critical to understanding how it behaves within a circuit and contributes to behavior since the firing of an action potential is how neurons communicate with each other and with muscles. The electrophysiological changes of motoneurons over development underlies how their function changes over the lifetime of an organism. After describing the properties of individual motoneurons, the chapter then turns to revealing how motoneurons interact within complex neural circuits, with other motoneurons as well as sensory neurons, and how these circuits change over development. Finally, this chapter ends with highlighting some recent advances made in motoneuron pathology, focusing on spinal muscular atrophy, amyotrophic lateral sclerosis, and axotomy.
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Affiliation(s)
- Joshua I Chalif
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA
- Department of Neurosurgery, Brigham and Women's Hospital, Harvard University, Boston, MA, USA
| | - George Z Mentis
- Departments of Neurology and Pathology & Cell Biology, Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, USA.
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26
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Spinal muscular atrophy: Where are we now? Current challenges and high hopes. POSTEP HIG MED DOSW 2022. [DOI: 10.2478/ahem-2022-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Spinal muscular atrophy (SMA) is a neuromuscular disorder characterized by muscle weakness. It causes movement issues and severe physical disability. SMA is classified into four types based on the level of function achieved, age of onset, and maximum function achieved. The deletion or point mutation in the Survival of Motor Neuron 1 (SMN1) gene causes SMA. As a result, no full-length protein is produced. A nearly identical paralog, SMN2, provides enough stable protein to prevent death but not enough to compensate for SMN1's loss. The difference between SMN1 and SMN2 is due to different exon 7 alternative splicing patterns. SMA molecular therapies currently focus on restoring functional SMN protein by splicing modification of SMN2 exon 7 or elevated SMN protein levels. Nusinersen, an antisense oligonucleotide targeting the ISS-N1 sequence in SMN2 intron 7, was the first drug approved by the Food and Drug Administration. Risdiplam, a novel therapeutic that acts as an SMN2 exon 7 splicing modifier, was recently approved. All of these drugs result in the inclusion of SMN2 exon 7, and thus the production of functional SMN protein. Onasemnogene abeparvovec is a gene therapy that uses a recombinant adeno-associated virus that encodes the SMN protein. There are also experimental therapies available, such as reldesemtiv and apitegromab (SRK-015), which focus on improving muscle function or increasing muscle tissue growth, respectively. Although approved therapies have been shown to be effective, not all SMA patients can benefit from them due to age or weight, but primarily due to their high cost. This demonstrates the significance of continuous treatment improvement in today's medical challenges.
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27
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Lotti F, Przedborski S. Motoneuron Diseases. ADVANCES IN NEUROBIOLOGY 2022; 28:323-352. [PMID: 36066831 DOI: 10.1007/978-3-031-07167-6_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Motoneuron diseases (MNDs) represent a heterogeneous group of progressive paralytic disorders, mainly characterized by the loss of upper (corticospinal) motoneurons, lower (spinal) motoneurons or, often both. MNDs can occur from birth to adulthood and have a highly variable clinical presentation, even within gene-positive forms, suggesting the existence of environmental and genetic modifiers. A combination of cell autonomous and non-cell autonomous mechanisms contributes to motoneuron degeneration in MNDs, suggesting multifactorial pathogenic processes.
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Affiliation(s)
- Francesco Lotti
- Departments of Neurology, Pathology & Cell Biology, and Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Serge Przedborski
- Departments of Neurology, Pathology & Cell Biology, and Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
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28
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Zhang Y, Chen X, Wang Q, Du C, Lu W, Yuan H, Zhang Z, Li D, Ling X, Ren X, Zhao Y, Su Q, Xing Z, Qin Y, Yang X, Shen Y, Wu H, Qi Y. Hyper-SUMOylation of SMN induced by SENP2 deficiency decreases its stability and leads to spinal muscular atrophy-like pathology. J Mol Med (Berl) 2021; 99:1797-1813. [PMID: 34628513 DOI: 10.1007/s00109-021-02130-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/05/2021] [Accepted: 08/09/2021] [Indexed: 11/28/2022]
Abstract
Spinal muscular atrophy (SMA), a degenerative motor neuron disease and a leading cause of infant mortality, is caused by loss of functional survival motor neuron (SMN) protein due to SMN1 gene mutation. Here, using mouse and cell models for behavioral and histological studies, we found that SENP2 (SUMO/sentrin-specific protease 2)-deficient mice developed a notable SMA-like pathology phenotype with significantly decreased muscle fibers and motor neurons. At the molecular level, SENP2 deficiency in mice did not affect transcription but decreased SMN protein levels by promoting the SUMOylation of SMN. SMN was modified by SUMO2 with the E3 PIAS2α and deconjugated by SENP2. SUMOylation of SMN accelerated its degradation by the ubiquitin-proteasome degradation pathway with the ubiquitin E1 UBA1 (ubiquitin-like modifier activating enzyme 1) and E3 ITCH. SUMOylation of SMN increased its acetylation to inhibit the formation of Cajal bodies (CBs). These results showed that SENP2 deficiency induced hyper-SUMOylation of the SMN protein, which further affected the stability and functions of the SMN protein, eventually leading to the SMA-like phenotype. Thus, we uncovered the important roles for hyper-SUMOylation of SMN induced by SENP2 deficiency in motor neurons and provided a novel targeted therapeutic strategy for SMA. KEY MESSAGES: SENP2 deficiency enhanced the hyper-SUMOylation of SMN and promoted the degradation of SMN by the ubiquitin-proteasome pathway. SUMOylation increased the acetylation of SMN to inhibit CB formation. SENP2 deficiency caused hyper-SUMOylation of SMN protein, which further affected the stability and functions of SMN protein and eventually led to the occurrence of SMA-like pathology.
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Affiliation(s)
- Yuhong Zhang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Xu Chen
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Qiqi Wang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Congcong Du
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Wenbin Lu
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Hong Yuan
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Zhenzhen Zhang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Danqing Li
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Xing Ling
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Xiang Ren
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Yang Zhao
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Qi Su
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Zhengcao Xing
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Yuanyuan Qin
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Xinyi Yang
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Yajie Shen
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China
| | - Hongmei Wu
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China.
| | - Yitao Qi
- Key Laboratory of the Ministry of Education for Medicinal Resources and Natural Pharmaceutical Chemistry, National Engineering Laboratory for Resource Developing of Endangered Chinese Crude Drugs in Northwest of China, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, Shaanxi, China.
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29
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Mirea A, Shelby ES, Axente M, Badina M, Padure L, Leanca M, Dima V, Sporea C. Combination Therapy with Nusinersen and Onasemnogene Abeparvovec-xioi in Spinal Muscular Atrophy Type I. J Clin Med 2021; 10:jcm10235540. [PMID: 34884240 PMCID: PMC8658131 DOI: 10.3390/jcm10235540] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/22/2021] [Accepted: 11/25/2021] [Indexed: 01/12/2023] Open
Abstract
Background: Spinal muscular atrophy (SMA) is a neuromuscular progressive disease, characterized by decreased amounts of survival motor neuron (SMN) protein, due to an autosomal recessive genetic defect. Despite recent research, there is still no cure. Nusinersen, an antisense oligonucleotide acting on the SMN2 gene, is intrathecally administered all life long, while onasemnogene abeparvovec-xioi, a gene therapy, is administered intravenously only once. Both therapies have proven efficacy, with best outcomes obtained when administered presymptomatically. In recent years, disease-modifying therapies such as nusinersen and onasemnogene abeparvovec-xioi have changed the natural history of SMA. Methods: We observed seven SMA type I patients, who received both therapies. We compared their motor function trajectories, ventilation hours and cough assist sessions to a control group of patients who received one therapy, in order to investigate whether combination therapy may be more effective than a single intervention alone. Results: Patients who received both therapies, compared to the monotherapy cohort, had the same motor function trajectory. Moreover, it was observed that the evolution of motor function was better in the 6 months following the first therapy than in the first 6 months after adding the second treatment. Conclusions: Our results suggest that early treatment is more important than combined therapy.
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Affiliation(s)
- Andrada Mirea
- Faculty of Midwifery and Nursing, University of Medicine and Pharmacy “Carol Davila”, 37 Dionisie Lupu Street, 020021 Bucharest, Romania; (M.A.); (M.B.); (C.S.)
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
- Correspondence:
| | - Elena-Silvia Shelby
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
| | - Mihaela Axente
- Faculty of Midwifery and Nursing, University of Medicine and Pharmacy “Carol Davila”, 37 Dionisie Lupu Street, 020021 Bucharest, Romania; (M.A.); (M.B.); (C.S.)
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
| | - Mihaela Badina
- Faculty of Midwifery and Nursing, University of Medicine and Pharmacy “Carol Davila”, 37 Dionisie Lupu Street, 020021 Bucharest, Romania; (M.A.); (M.B.); (C.S.)
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
| | - Liliana Padure
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
| | - Madalina Leanca
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
| | - Vlad Dima
- Clinical Hospital of Obstetrics and Gynecology “Filantropia”, 11 Ion Mihalache Avenue, 011132 Bucharest, Romania;
| | - Corina Sporea
- Faculty of Midwifery and Nursing, University of Medicine and Pharmacy “Carol Davila”, 37 Dionisie Lupu Street, 020021 Bucharest, Romania; (M.A.); (M.B.); (C.S.)
- Scientific Research Nucleus, National University Center for Children Neurorehabilitation “Dr. Nicolae Robanescu”, 44 Dumitru Minca Street, 041408 Bucharest, Romania; (E.-S.S.); (L.P.); (M.L.)
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Buettner JM, Sime Longang JK, Gerstner F, Apel KS, Blanco-Redondo B, Sowoidnich L, Janzen E, Langenhan T, Wirth B, Simon CM. Central synaptopathy is the most conserved feature of motor circuit pathology across spinal muscular atrophy mouse models. iScience 2021; 24:103376. [PMID: 34825141 PMCID: PMC8605199 DOI: 10.1016/j.isci.2021.103376] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 10/12/2021] [Accepted: 10/26/2021] [Indexed: 11/04/2022] Open
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by reduced survival motor neuron (SMN) protein. Recently, SMN dysfunction has been linked to individual aspects of motor circuit pathology in a severe SMA mouse model. To determine whether these disease mechanisms are conserved, we directly compared the motor circuit pathology of three SMA mouse models. The severe SMNΔ7 model exhibits vast motor circuit defects, including degeneration of motor neurons, spinal excitatory synapses, and neuromuscular junctions (NMJs). In contrast, the Taiwanese model shows very mild motor neuron pathology, but early central synaptic loss. In the intermediate Smn2B/- model, strong pathology of central excitatory synapses and NMJs precedes the late onset of p53-dependent motor neuron death. These pathological events correlate with SMN-dependent splicing dysregulation of specific mRNAs. Our study provides a knowledge base for properly tailoring future studies and identifies central excitatory synaptopathy as a key feature of motor circuit pathology in SMA. Comparison of detailed motor circuit pathology across three SMA mouse models Motor circuit pathology correlates with dysregulation of specific mRNAs Motor neuron death in severe and intermediate SMA models is p53-dependent Central excitatory synaptopathy is the most conserved feature of SMA pathology
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Affiliation(s)
- Jannik M Buettner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | | | - Florian Gerstner
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Katharina S Apel
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Beatriz Blanco-Redondo
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Leonie Sowoidnich
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
| | - Eva Janzen
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany
| | - Tobias Langenhan
- Rudolf Schönheimer Institute of Biochemistry, Division of General Biochemistry, Medical Faculty, Leipzig University, Leipzig 04103, Germany
| | - Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Institute for Genetics, University of Cologne, Cologne, Germany.,Center for Rare Diseases Cologne, University Hospital of Cologne, Cologne, Germany
| | - Christian M Simon
- Carl-Ludwig-Institute for Physiology, Leipzig University, Leipzig 04103, Germany
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McGovern VL, Kray KM, Arnold WD, Duque SI, Iyer CC, Massoni-Laporte A, Workman E, Patel A, Battle DJ, Burghes AHM. Intragenic complementation of amino and carboxy terminal SMN missense mutations can rescue Smn null mice. Hum Mol Genet 2021; 29:3493-3503. [PMID: 33084884 DOI: 10.1093/hmg/ddaa235] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/18/2020] [Accepted: 10/15/2020] [Indexed: 01/15/2023] Open
Abstract
Spinal muscular atrophy is caused by reduced levels of SMN resulting from the loss of SMN1 and reliance on SMN2 for the production of SMN. Loss of SMN entirely is embryonic lethal in mammals. There are several SMN missense mutations found in humans. These alleles do not show partial function in the absence of wild-type SMN and cannot rescue a null Smn allele in mice. However, these human SMN missense allele transgenes can rescue a null Smn allele when SMN2 is present. We find that the N- and C-terminal regions constitute two independent domains of SMN that can be separated genetically and undergo intragenic complementation. These SMN protein heteromers restore snRNP assembly of Sm proteins onto snRNA and completely rescue both survival of Smn null mice and motor neuron electrophysiology demonstrating that the essential functional unit of SMN is the oligomer.
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Affiliation(s)
- Vicki L McGovern
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Kaitlyn M Kray
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - W David Arnold
- Department of Neurology, The Ohio State University, Columbus, OH 43210, USA
| | - Sandra I Duque
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Chitra C Iyer
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Aurélie Massoni-Laporte
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Eileen Workman
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Aalapi Patel
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA
| | - Daniel J Battle
- Department of Biological Chemistry, The Ohio State University, Columbus, OH 43210, USA
| | - Arthur H M Burghes
- Department of Biological Chemistry and Pharmacology, The Ohio State University, Columbus, OH 43210, USA.,Department of Neurology, The Ohio State University, Columbus, OH 43210, USA.,Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA
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32
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Chong LC, Gandhi G, Lee JM, Yeo WWY, Choi SB. Drug Discovery of Spinal Muscular Atrophy (SMA) from the Computational Perspective: A Comprehensive Review. Int J Mol Sci 2021; 22:8962. [PMID: 34445667 PMCID: PMC8396480 DOI: 10.3390/ijms22168962] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 01/27/2021] [Indexed: 01/02/2023] Open
Abstract
Spinal muscular atrophy (SMA), one of the leading inherited causes of child mortality, is a rare neuromuscular disease arising from loss-of-function mutations of the survival motor neuron 1 (SMN1) gene, which encodes the SMN protein. When lacking the SMN protein in neurons, patients suffer from muscle weakness and atrophy, and in the severe cases, respiratory failure and death. Several therapeutic approaches show promise with human testing and three medications have been approved by the U.S. Food and Drug Administration (FDA) to date. Despite the shown promise of these approved therapies, there are some crucial limitations, one of the most important being the cost. The FDA-approved drugs are high-priced and are shortlisted among the most expensive treatments in the world. The price is still far beyond affordable and may serve as a burden for patients. The blooming of the biomedical data and advancement of computational approaches have opened new possibilities for SMA therapeutic development. This article highlights the present status of computationally aided approaches, including in silico drug repurposing, network driven drug discovery as well as artificial intelligence (AI)-assisted drug discovery, and discusses the future prospects.
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Affiliation(s)
- Li Chuin Chong
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
| | - Gayatri Gandhi
- Perdana University Graduate School of Medicine, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (G.G.); (W.W.Y.Y.)
| | - Jian Ming Lee
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
| | - Wendy Wai Yeng Yeo
- Perdana University Graduate School of Medicine, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (G.G.); (W.W.Y.Y.)
| | - Sy-Bing Choi
- Centre for Bioinformatics, School of Data Sciences, Perdana University, Suite 9.2, 9th Floor, Wisma Chase Perdana, Changkat Semantan, Kuala Lumpur 50490, Malaysia; (L.C.C.); (J.M.L.)
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Sumoylation regulates the assembly and activity of the SMN complex. Nat Commun 2021; 12:5040. [PMID: 34413305 PMCID: PMC8376998 DOI: 10.1038/s41467-021-25272-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 07/26/2021] [Indexed: 11/09/2022] Open
Abstract
SMN is a ubiquitously expressed protein and is essential for life. SMN deficiency causes the neurodegenerative disease spinal muscular atrophy (SMA), the leading genetic cause of infant mortality. SMN interacts with itself and other proteins to form a complex that functions in the assembly of ribonucleoproteins. SMN is modified by SUMO (Small Ubiquitin-like Modifier), but whether sumoylation is required for the functions of SMN that are relevant to SMA pathogenesis is not known. Here, we show that inactivation of a SUMO-interacting motif (SIM) alters SMN sub-cellular distribution, the integrity of its complex, and its function in small nuclear ribonucleoproteins biogenesis. Expression of a SIM-inactivated mutant of SMN in a mouse model of SMA slightly extends survival rate with limited and transient correction of motor deficits. Remarkably, although SIM-inactivated SMN attenuates motor neuron loss and improves neuromuscular junction synapses, it fails to prevent the loss of sensory-motor synapses. These findings suggest that sumoylation is important for proper assembly and function of the SMN complex and that loss of this post-translational modification impairs the ability of SMN to correct selective deficits in the sensory-motor circuit of SMA mice.
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Abstract
PURPOSE OF REVIEW This article provides an overview of the pathophysiology and clinical presentations of spinal muscular atrophy (SMA) and reviews therapeutic developments, including US Food and Drug Administration (FDA)-approved gene-targeted therapies and mainstays of supportive SMA care. RECENT FINDINGS Over the past decades, an understanding of the role of SMN protein in the development and maintenance of the motor unit and the intricate genetics underlying SMA has led to striking developments in therapeutics with three FDA-approved treatments for SMA, one targeting SMN1 gene replacement (onasemnogene abeparvovec-xioi) and two others enhancing SMN protein production from the SMN2 gene (nusinersen and risdiplam). These therapies are most effective in infants treated at younger ages, and improvement is most striking in babies treated as neonates. Despite improvements in motor function, patients (especially those treated at older ages) continue to experience significant weakness and require continued close monitoring of respiratory and orthopedic symptoms. SUMMARY Striking therapeutic advancements have changed the clinical course of SMA dramatically, although supportive care continues to play an important role in patient care.
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Van Alstyne M, Tattoli I, Delestree N, Recinos Y, Workman E, Shihabuddin LS, Zhang C, Mentis GZ, Pellizzoni L. Gain of toxic function by long-term AAV9-mediated SMN overexpression in the sensorimotor circuit. Nat Neurosci 2021; 24:930-940. [PMID: 33795885 PMCID: PMC8254787 DOI: 10.1038/s41593-021-00827-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 30.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 02/24/2021] [Indexed: 02/01/2023]
Abstract
The neurodegenerative disease spinal muscular atrophy (SMA) is caused by deficiency in the survival motor neuron (SMN) protein. Currently approved SMA treatments aim to restore SMN, but the potential for SMN expression beyond physiological levels is a unique feature of adeno-associated virus serotype 9 (AAV9)-SMN gene therapy. Here, we show that long-term AAV9-mediated SMN overexpression in mouse models induces dose-dependent, late-onset motor dysfunction associated with loss of proprioceptive synapses and neurodegeneration. Mechanistically, aggregation of overexpressed SMN in the cytoplasm of motor circuit neurons sequesters components of small nuclear ribonucleoproteins, leading to splicing dysregulation and widespread transcriptome abnormalities with prominent signatures of neuroinflammation and the innate immune response. Thus, long-term SMN overexpression interferes with RNA regulation and triggers SMA-like pathogenic events through toxic gain-of-function mechanisms. These unanticipated, SMN-dependent and neuron-specific liabilities warrant caution on the long-term safety of treating individuals with SMA with AAV9-SMN and the risks of uncontrolled protein expression by gene therapy.
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Affiliation(s)
- Meaghan Van Alstyne
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Ivan Tattoli
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032
| | - Nicolas Delestree
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Yocelyn Recinos
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Systems Biology, Columbia University, New York, NY 10032,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - Eileen Workman
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032
| | | | - Chaolin Zhang
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Systems Biology, Columbia University, New York, NY 10032,Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032
| | - George Z. Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY, 10032,Department of Pathology and Cell Biology, Columbia University, New York, NY, 10032,Department of Neurology, Columbia University, New York, NY, 10032,Address correspondence to: Livio Pellizzoni, Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, 630 West 168TH Street, New York, NY, 10032. Phone: +1 212-305-3046;
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36
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Minor Intron Splicing from Basic Science to Disease. Int J Mol Sci 2021; 22:ijms22116062. [PMID: 34199764 PMCID: PMC8199999 DOI: 10.3390/ijms22116062] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 01/14/2023] Open
Abstract
Pre-mRNA splicing is an essential step in gene expression and is catalyzed by two machineries in eukaryotes: the major (U2 type) and minor (U12 type) spliceosomes. While the majority of introns in humans are U2 type, less than 0.4% are U12 type, also known as minor introns (mi-INTs), and require a specialized spliceosome composed of U11, U12, U4atac, U5, and U6atac snRNPs. The high evolutionary conservation and apparent splicing inefficiency of U12 introns have set them apart from their major counterparts and led to speculations on the purpose for their existence. However, recent studies challenged the simple concept of mi-INTs splicing inefficiency due to low abundance of their spliceosome and confirmed their regulatory role in alternative splicing, significantly impacting the expression of their host genes. Additionally, a growing list of minor spliceosome-associated diseases with tissue-specific pathologies affirmed the importance of minor splicing as a key regulatory pathway, which when deregulated could lead to tissue-specific pathologies due to specific alterations in the expression of some minor-intron-containing genes. Consequently, uncovering how mi-INTs splicing is regulated in a tissue-specific manner would allow for better understanding of disease pathogenesis and pave the way for novel therapies, which we highlight in this review.
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Prigodich AE, Wang S, Verhoest P, Warne N, Allerton C, Burkhardt J, Fernando K, Dolsten M. Innovation in breakthrough drugs and vaccines: Development risk, patient impact, and value. Drug Discov Today 2021; 26:2232-2237. [PMID: 34015542 DOI: 10.1016/j.drudis.2021.05.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 04/21/2021] [Accepted: 05/10/2021] [Indexed: 11/26/2022]
Abstract
Innovation has a crucial role in developing breakthrough drugs and vaccines that can change patients' lives. To better understand this role, we evaluated recent outcomes for assets developed using different types of innovation. Although all approaches have delivered breakthroughs, assets that modulate established biological targets with innovative scientific or technological designs provide a unique combination of reduced development risk, high patient impact, and high commercial value. This type of asset currently represents a relatively small proportion of approved drugs and vaccines, but we anticipate that an increasing body of scientific knowledge and ongoing technological advancements could offer opportunities to grow this category in the future.
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Affiliation(s)
| | - Shuntai Wang
- Worldwide Research, Development and Medical, Pfizer Inc, United States
| | - Patrick Verhoest
- Worldwide Research, Development and Medical, Pfizer Inc, United States
| | - Nicholas Warne
- Worldwide Research, Development and Medical, Pfizer Inc, United States
| | | | - John Burkhardt
- Worldwide Research, Development and Medical, Pfizer Inc, United States
| | - Kathy Fernando
- Worldwide Research, Development and Medical, Pfizer Inc, United States
| | - Mikael Dolsten
- Worldwide Research, Development and Medical, Pfizer Inc, United States.
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38
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Gandhi G, Abdullah S, Foead AI, Yeo WWY. The potential role of miRNA therapies in spinal muscle atrophy. J Neurol Sci 2021; 427:117485. [PMID: 34015517 DOI: 10.1016/j.jns.2021.117485] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/14/2021] [Accepted: 05/10/2021] [Indexed: 01/15/2023]
Abstract
Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by low levels of full-length survival motor neuron (SMN) protein due to the loss of the survival motor neuron 1 (SMN1) gene and inefficient splicing of the survival motor neuron 2 (SMN2) gene, which mostly affects alpha motor neurons of the lower spinal cord. Despite the U.S. Food and Drug Administration (FDA) approved SMN-dependent therapies including Nusinersen, Zolgensma® and Evrysdi™, SMA is still a devastating disease as these existing expensive drugs may not be sufficient and thus, remains a need for additional therapies. The involvement of microRNAs (miRNAs) in SMA is expanding because miRNAs are important mediators of gene expression as each miRNA could target a number of genes. Hence, miRNA-based therapy could be utilized in treating this genetic disorder. However, the delivery of miRNAs into the target cells remains an obstacle in SMA, as there is no effective delivery system to date. This review highlights the potential strategies for intracellular miRNA delivery into target cells and current challenges in miRNA delivery. Furthermore, we provide the future prospects of miRNA-based therapeutic strategies in SMA.
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Affiliation(s)
- Gayatri Gandhi
- Perdana University Graduate School of Medicine, Perdana University, Wisma Chase Perdana, Changkat Semantan, Damansara Heights, 50490 Kuala Lumpur, Malaysia
| | - Syahril Abdullah
- Medical Genetics Laboratory, Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, Universiti Putra Malaysia, 43400 UPM, Selangor, Malaysia; Genetics & Regenerative Medicine Research Centre, Faculty of Medicine and Health Sciences, Universiti Putra Malaysia, 43400 UPM, Selangor, Malaysia; UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM, Selangor, Malaysia
| | - Agus Iwan Foead
- Department of Orthopedics, Perdana University-Royal College of Surgeons in Ireland, Perdana University, Wisma Chase Perdana, Changkat Semantan, Damansara Heights, 50490 Kuala Lumpur, Malaysia
| | - Wendy Wai Yeng Yeo
- Perdana University Graduate School of Medicine, Perdana University, Wisma Chase Perdana, Changkat Semantan, Damansara Heights, 50490 Kuala Lumpur, Malaysia.
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Sansa A, de la Fuente S, Comella JX, Garcera A, Soler RM. Intracellular pathways involved in cell survival are deregulated in mouse and human spinal muscular atrophy motoneurons. Neurobiol Dis 2021; 155:105366. [PMID: 33845129 DOI: 10.1016/j.nbd.2021.105366] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 03/18/2021] [Accepted: 04/07/2021] [Indexed: 12/14/2022] Open
Abstract
Spinal Muscular Atrophy (SMA) is a severe neuromuscular disorder caused by loss of the Survival Motor Neuron 1 gene (SMN1). Due to this depletion of the survival motor neuron (SMN) protein, the disease is characterized by the degeneration of spinal cord motoneurons (MNs), progressive muscular atrophy, and weakness. Nevertheless, the ultimate cellular and molecular mechanisms leading to cell loss in SMN-reduced MNs are only partially known. We have investigated the activation of apoptotic and neuronal survival pathways in several models of SMA cells. Even though the antiapoptotic proteins FAIM-L and XIAP were increased in SMA MNs, the apoptosis executioner cleaved-caspase-3 was also elevated in these cells, suggesting the activation of the apoptosis process. Analysis of the survival pathway PI3K/Akt showed that Akt phosphorylation was reduced in SMA MNs and pharmacological inhibition of PI3K diminished SMN and Gemin2 at transcriptional level in control MNs. In contrast, ERK phosphorylation was increased in cultured mouse and human SMA MNs. Our observations suggest that apoptosis is activated in SMA MNs and that Akt phosphorylation reduction may control cell degeneration, thereby regulating the transcription of Smn and other genes related to SMN function.
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Affiliation(s)
- Alba Sansa
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Sandra de la Fuente
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Joan X Comella
- CIBERNED & Cell Signaling and Apoptosis Group, Vall d'Hebron Research Institute (VHIR), 08035, Barcelona, Spain
| | - Ana Garcera
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain
| | - Rosa M Soler
- Neuronal Signaling Unit, Experimental Medicine Department, Universitat de Lleida-IRBLleida, Rovira Roure, 80, 25198, Lleida, Spain..
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Chand D, Mohr F, McMillan H, Tukov FF, Montgomery K, Kleyn A, Sun R, Tauscher-Wisniewski S, Kaufmann P, Kullak-Ublick G. Hepatotoxicity following administration of onasemnogene abeparvovec (AVXS-101) for the treatment of spinal muscular atrophy. J Hepatol 2021; 74:560-566. [PMID: 33186633 DOI: 10.1016/j.jhep.2020.11.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/28/2020] [Accepted: 11/03/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS Spinal muscular atrophy (SMA) is an autosomal recessive, childhood-onset motor neuron disease. Onasemnogene abeparvovec (OA) is a gene therapy designed to address SMA's root cause. In pivotal mouse toxicology studies, the liver was identified as a major site of OA toxicity. Clinical data reflect elevations in serum aminotransferase concentrations, with some reports of serious acute liver injury. Prophylactic prednisolone mitigates these effects. Herein, we aim to provide pragmatic, supportive guidance for identification, management, and risk mitigation of potential drug-induced liver injury. METHODS Data from 325 patients with SMA who had received OA through 31 December 2019, in 5 clinical trials, a managed access program (MAP), and a long-term registry (RESTORE), and through commercial use, were analyzed. Liver-related adverse events, laboratory data, concomitant medications, and prednisolone use were analyzed. RESULTS Based on adverse events and laboratory data, 90 of 100 patients had elevated liver function test results (alanine aminotransferase, and/or aspartate aminotransferase, and/or bilirubin concentrations). Of these, liver-associated adverse events were reported for 34 of 100 (34%) and 10 of 43 (23%) patients in clinical trials and MAP/RESTORE, respectively. Two patients in MAP had serious acute liver injury, which resolved completely. While all events in the overall population resolved, prednisolone treatment duration varied (range: 33-229 days), with a majority receiving prednisolone for 60-120 days. More than 60% had elevations in either alanine aminotransferase, aspartate aminotransferase, or bilirubin concentrations prior to dosing. Greater than 40% received potentially hepatotoxic concomitant medications. CONCLUSIONS Hepatotoxicity is a known risk associated with OA use. Practitioners should identify contributing factors and mitigate risk through appropriate monitoring and intervention. LAY SUMMARY Onasemnogene abeparvovec is a type of medicine called a "gene therapy," which is used to treat babies and young children who have a rare, serious inherited condition called "spinal muscular atrophy" (SMA). It works by supplying a fully functioning copy of the survival motor neuron or SMN gene, which then helps the body produce enough SMN protein. However, it can cause an immune response that could lead to an increase in enzymes produced by the liver. This article provides information about the liver injury and how to prevent and recognize if it happens, so that it may be treated properly.
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Affiliation(s)
- Deepa Chand
- Novartis Gene Therapies, Bannockburn, IL, United States; Department of Pediatrics, Washington University School of Medicine, St. Louis, MO, United States.
| | | | - Hugh McMillan
- Department of Pediatrics, Children's Hospital of Eastern Ontario, and University of Ottawa, Ottawa, ON, Canada
| | | | | | - Aaron Kleyn
- Novartis Gene Therapies, Bannockburn, IL, United States
| | - Rui Sun
- Novartis Gene Therapies, Bannockburn, IL, United States
| | | | | | - Gerd Kullak-Ublick
- Novartis International AG, Basel, Switzerland; Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
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In Search of a Cure: The Development of Therapeutics to Alter the Progression of Spinal Muscular Atrophy. Brain Sci 2021; 11:brainsci11020194. [PMID: 33562482 PMCID: PMC7915832 DOI: 10.3390/brainsci11020194] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
Until the recent development of disease-modifying therapeutics, spinal muscular atrophy (SMA) was considered a devastating neuromuscular disease with a poor prognosis for most affected individuals. Symptoms generally present during early childhood and manifest as muscle weakness and progressive paralysis, severely compromising the affected individual’s quality of life, independence, and lifespan. SMA is most commonly caused by the inheritance of homozygously deleted SMN1 alleles with retention of one or more copies of a paralog gene, SMN2, which inversely correlates with disease severity. The recent advent and use of genetically targeted therapies have transformed SMA into a prototype for monogenic disease treatment in the era of genetic medicine. Many SMA-affected individuals receiving these therapies achieve traditionally unobtainable motor milestones and survival rates as medicines drastically alter the natural progression of this disease. This review discusses historical SMA progression and underlying disease mechanisms, highlights advances made in therapeutic research, clinical trials, and FDA-approved medicines, and discusses possible second-generation and complementary medicines as well as optimal temporal intervention windows in order to optimize motor function and improve quality of life for all SMA-affected individuals.
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42
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Wirth B. Spinal Muscular Atrophy: In the Challenge Lies a Solution. Trends Neurosci 2021; 44:306-322. [PMID: 33423791 DOI: 10.1016/j.tins.2020.11.009] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Revised: 11/08/2020] [Accepted: 11/30/2020] [Indexed: 12/16/2022]
Abstract
The path from gene discovery to therapy in spinal muscular atrophy (SMA) has been a highly challenging endeavor, but also led to one of the most successful stories in neurogenetics. In SMA, a neuromuscular disorder with an often fatal outcome until recently, with those affected never able to sit, stand, or walk, children now achieve these motoric abilities and almost age-based development when treated presymptomatically. This review summarizes the challenges along this 30-year journey. It is also meant to inspire early-career scientists not to give up when things become difficult but to try to uncover the biological underpinnings and transform the challenge into the next big discovery. Without doubt, the improvements seen with the three therapeutic strategies in SMA are impressive; many open questions remain and are discussed in this review.
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Affiliation(s)
- Brunhilde Wirth
- Institute of Human Genetics, Center for Molecular Medicine, Center for Rare Disorders, University of Cologne, Kerpener Str. 34, 50931 Cologne, Germany.
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Detection of SMN1 to SMN2 gene conversion events and partial SMN1 gene deletions using array digital PCR. Neurogenetics 2021; 22:53-64. [PMID: 33415588 DOI: 10.1007/s10048-020-00630-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/26/2020] [Indexed: 12/15/2022]
Abstract
Proximal spinal muscular atrophy (SMA), a leading genetic cause of infant death worldwide, is an early-onset motor neuron disease characterized by loss of α-motor neurons and associated muscle atrophy. SMA is caused by deletion or other disabling mutations of survival motor neuron 1 (SMN1) but retention of one or more copies of the paralog SMN2. Within the SMA population, there is substantial variation in SMN2 copy number (CN); in general, those individuals with SMA who have a high SMN2 CN have a milder disease. Because SMN2 functions as a disease modifier, its accurate CN determination may have clinical relevance. In this study, we describe the development of array digital PCR (dPCR) to quantify SMN1 and SMN2 CNs in DNA samples using probes that can distinguish the single nucleotide difference between SMN1 and SMN2 in exon 8. This set of dPCR assays can accurately and reliably measure the number of SMN1 and SMN2 copies in DNA samples. In a cohort of SMA patient-derived cell lines, the assay confirmed a strong inverse correlation between SMN2 CN and disease severity. We can detect SMN1-SMN2 gene conversion events in DNA samples by comparing CNs at exon 7 and exon 8. Partial deletions of SMN1 can also be detected with dPCR by comparing CNs at exon 7 or exon 8 with those at intron 1. Array dPCR is a practical technique to determine, accurately and reliably, SMN1 and SMN2 CNs from SMA samples as well as identify gene conversion events and partial deletions of SMN1.
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AlRuthia Y, Almuaythir GS, H Alrasheed H, Alsharif WR, Temsah MH, Alsohime F, Sales I, Alwhaibi M, Bashiri FA. Proxy-Reported Quality of Life and Access to Nusinersen Among Patients with Spinal Muscular Atrophy in Saudi Arabia. Patient Prefer Adherence 2021; 15:729-739. [PMID: 33880016 PMCID: PMC8053517 DOI: 10.2147/ppa.s305849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The recent approval of innovative therapies for spinal muscular atrophy (SMA), such as nusinersen, has brought hope to patients and their families. OBJECTIVE The aims of this study were to compare the characteristics and HRQoL of SMA patients treated with nusinersen and those treated with the standard of care. METHODS This was a cross-sectional, interviewer-administered telephone questionnaire, which used a purposive sampling of SMA patients through a social support network. EuroQol five-dimensions-3-level (EQ-5D-3L) and the visual analog scale (VAS) have been used to assess the HRQoL. Different descriptive and inferential tests have been performed to compare the characteristics, EQ-5D responses, and mean scores of EQ-VAS between patients on nusinersen and the standard of care. RESULTS Eleven out of 36 SMA patients (30.55%) have been treated with nusinersen. Patients with type I SMA represented 54% of those treated with nusinersen (P=0.012). Only 12.5% of SMA patients living in the Mecca region are treated with nusinersen in comparison to 50% of patients living in the Riyadh region (P=0.029). No difference was noticed in the proxy-responses for the five domains of the EQ-5D or the mean VAS scores for patients on nusinersen and the standard of care despite controlling for the SMA type and the ability to breathe independently (β= 1.39, 95% CI= - 5.15-7.93, P=0.667). However, the mean VAS score for patients who are unable to breathe independently was significantly lower than their counterparts who are able to breathe independently even after controlling for the SMA type and nusinersen treatment (β= -31.61, 95% CI= - 51.59 - -11.63, P=0.003). CONCLUSION The results of this study highlight the uncertainty about the impact of nusinersen on SMA patients' HRQoL. Therefore, the impact of nusinersen on HRQoL should be examined using more robust study designs.
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Affiliation(s)
- Yazed AlRuthia
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
- Pharmacoeconomics Research Unit, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
- Correspondence: Yazed AlRuthia Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi ArabiaTel +996 114677483Fax +966 114677480 Email
| | - Ghadah S Almuaythir
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Hala H Alrasheed
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Wejdan R Alsharif
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Mohamad-Hani Temsah
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Pediatric Intensive Care Unit, Pediatric Department, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Fahad Alsohime
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Pediatric Intensive Care Unit, Pediatric Department, King Saud University Medical City, Riyadh, Saudi Arabia
| | - Ibrahim Sales
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Monira Alwhaibi
- Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Fahad A Bashiri
- College of Medicine, King Saud University, Riyadh, Saudi Arabia
- Division of Neurology, Department of Pediatrics, King Saud University Medical City, Riyadh, Saudi Arabia
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Gollapalli K, Kim JK, Monani UR. Emerging concepts underlying selective neuromuscular dysfunction in infantile-onset spinal muscular atrophy. Neural Regen Res 2021; 16:1978-1984. [PMID: 33642371 PMCID: PMC8343306 DOI: 10.4103/1673-5374.308073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Infantile-onset spinal muscular atrophy is the quintessential example of a disorder characterized by a predominantly neurodegenerative phenotype that nevertheless stems from perturbations in a housekeeping protein. Resulting from low levels of the Survival of Motor Neuron (SMN) protein, spinal muscular atrophy manifests mainly as a lower motor neuron disease. Why this is so and whether other cell types contribute to the classic spinal muscular atrophy phenotype continue to be the subject of intense investigation and are only now gaining appreciation. Yet, what is emerging is sometimes as puzzling as it is instructive, arguing for a careful re-examination of recent study outcomes, raising questions about established dogma in the field and making the case for a greater focus on milder spinal muscular atrophy models as tools to identify key mechanisms driving selective neuromuscular dysfunction in the disease. This review examines the evidence for novel molecular and cellular mechanisms that have recently been implicated in spinal muscular atrophy, highlights breakthroughs, points out caveats and poses questions that ought to serve as the basis of new investigations to better understand and treat this and other more common neurodegenerative disorders.
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Affiliation(s)
- Kishore Gollapalli
- Department of Neurology; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY, USA
| | - Jeong-Ki Kim
- Department of Neurology; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY, USA
| | - Umrao R Monani
- Department of Neurology; Department of Pathology & Cell Biology; Center for Motor Neuron Biology and Disease, Columbia University Medical Center, New York, NY, USA
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Li YJ, Chen TH, Wu YZ, Tseng YH. Metabolic and Nutritional Issues Associated with Spinal Muscular Atrophy. Nutrients 2020; 12:nu12123842. [PMID: 33339220 PMCID: PMC7766651 DOI: 10.3390/nu12123842] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 12/02/2020] [Accepted: 12/15/2020] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy (SMA), the main genetic cause of infant death, is a neurodegenerative disease characterized by the selective loss of motor neurons in the anterior horn of the spinal cord, accompanied by muscle wasting. Pathomechanically, SMA is caused by low levels of the survival motor neuron protein (SMN) resulting from the loss of the SMN1 gene. However, emerging research extends the pathogenic effect of SMN deficiency beyond motor neurons. A variety of metabolic abnormalities, especially altered fatty acid metabolism and impaired glucose tolerance, has been described in isolated cases of SMA; therefore, the impact of SMN deficiency in metabolic abnormalities has been speculated. Although the life expectancy of these patients has increased due to novel disease-modifying therapies and standardization of care, understanding of the involvement of metabolism and nutrition in SMA is still limited. Optimal nutrition support and metabolic monitoring are essential for patients with SMA, and a comprehensive nutritional assessment can guide personalized nutritional therapy for this vulnerable population. It has recently been suggested that metabolomics studies before and after the onset of SMA in patients can provide valuable information about the direct or indirect effects of SMN deficiency on metabolic abnormalities. Furthermore, identifying and quantifying the specific metabolites in SMA patients may serve as an authentic biomarker or therapeutic target for SMA. Here, we review the main epidemiological and mechanistic findings that link metabolic changes to SMA and further discuss the principles of metabolomics as a novel approach to seek biomarkers and therapeutic insights in SMA.
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Affiliation(s)
- Yang-Jean Li
- Department of Pediatrics, Kaohsiung Municipal United Hospital, Kaohsiung 80455, Taiwan;
| | - Tai-Heng Chen
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
- School of Post-Baccalaureate Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
- Correspondence: ; Tel.: +886-7-312-1101; Fax: +886-7-321-2062
| | - Yan-Zhang Wu
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
| | - Yung-Hao Tseng
- Department of Pediatrics, Division of Pediatric Emergency, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Kaohsiung 80708, Taiwan; (Y.-Z.W.); (Y.-H.T.)
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Chronic Pharmacological Increase of Neuronal Activity Improves Sensory-Motor Dysfunction in Spinal Muscular Atrophy Mice. J Neurosci 2020; 41:376-389. [PMID: 33219005 DOI: 10.1523/jneurosci.2142-20.2020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 10/09/2020] [Accepted: 11/05/2020] [Indexed: 12/14/2022] Open
Abstract
Dysfunction of neuronal circuits is an important determinant of neurodegenerative diseases. Synaptic dysfunction, death, and intrinsic activity of neurons are thought to contribute to the demise of normal behavior in the disease state. However, the interplay between these major pathogenic events during disease progression is poorly understood. Spinal muscular atrophy (SMA) is a neurodegenerative disease caused by a deficiency in the ubiquitously expressed protein SMN and is characterized by motor neuron death, skeletal muscle atrophy, as well as dysfunction and loss of both central and peripheral excitatory synapses. These disease hallmarks result in an overall reduction of neuronal activity in the spinal sensory-motor circuit. Here, we show that increasing neuronal activity by chronic treatment with the FDA-approved potassium channel blocker 4-aminopyridine (4-AP) improves motor behavior in both sexes of a severe mouse model of SMA. 4-AP restores neurotransmission and number of proprioceptive synapses and neuromuscular junctions (NMJs), while having no effects on motor neuron death. In addition, 4-AP treatment with pharmacological inhibition of p53-dependent motor neuron death results in additive effects, leading to full correction of sensory-motor circuit pathology and enhanced phenotypic benefit in SMA mice. Our in vivo study reveals that 4-AP-induced increase of neuronal activity restores synaptic connectivity and function in the sensory-motor circuit to improve the SMA motor phenotype.SIGNIFICANCE STATEMENT Spinal muscular atrophy (SMA) is a neurodegenerative disease, characterized by synaptic loss, motor neuron death, and reduced neuronal activity in spinal sensory-motor circuits. However, whether these are parallel or dependent events is unclear. We show here that long-term increase of neuronal activity by the FDA-approved drug 4-aminopyridine (4-AP) rescues the number and function of central and peripheral synapses in a SMA mouse model, resulting in an improvement of the sensory-motor circuit and motor behavior. Combinatorial treatment of pharmacological inhibition of p53, which is responsible for motor neuron death and 4-AP, results in additive beneficial effects on the sensory-motor circuit in SMA. Thus, neuronal activity restores synaptic connections and improves significantly the severe SMA phenotype.
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Jiang L, Lin R, Gallagher S, Zayac A, Butchbach MER, Hung P. Development and validation of a 4-color multiplexing spinal muscular atrophy (SMA) genotyping assay on a novel integrated digital PCR instrument. Sci Rep 2020; 10:19892. [PMID: 33199817 PMCID: PMC7670453 DOI: 10.1038/s41598-020-76893-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Accepted: 11/02/2020] [Indexed: 01/30/2023] Open
Abstract
Digital PCR (dPCR) technology has been proven to be highly sensitive and accurate in detecting copy number variations (CNV). However, a higher-order multiplexing dPCR assay for measuring SMN1 and SMN2 copy numbers in spinal muscular atrophy (SMA) samples has not been reported. Described here is a rapid multiplex SMA dPCR genotyping assay run on a fully integrated dPCR instrument with five optical channels. The hydrolysis probe-based multiplex dPCR assay quantifies SMN1, SMN2, and the total SMN (SMN1 + SMN2) while using RPPH1 gene as an internal reference control. The quadruplex assay was evaluated with characterized control DNA samples and validated with 15 blinded clinical samples from a previously published study. SMN1 and SMN2 copy numbers were completely concordant with previous results for both the control and blinded samples. The dPCR-based SMA copy number determination was accomplished in 90 min with a walk-away workflow identical to real-time quantitative PCR (qPCR). In summary, presented here is a simple higher-order multiplexing solution on a novel digital PCR platform to meet the growing demand for SMA genotyping and prognostics.
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Affiliation(s)
- Lingxia Jiang
- Combinati Inc., 2450 Embarcadero Way, Palo Alto, CA, 94303, USA.
| | - Robert Lin
- Combinati Inc., 2450 Embarcadero Way, Palo Alto, CA, 94303, USA
| | - Steve Gallagher
- Combinati Inc., 2450 Embarcadero Way, Palo Alto, CA, 94303, USA
| | - Andrew Zayac
- Combinati Inc., 2450 Embarcadero Way, Palo Alto, CA, 94303, USA
| | - Matthew E R Butchbach
- Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.,Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.,Department of Pediatrics, Sidney Kimmel College of Medicine, Thomas Jefferson University, Philadelphia, PA, USA.,Department of Biological Sciences, University of Delaware, Newark, DE, USA
| | - Paul Hung
- Combinati Inc., 2450 Embarcadero Way, Palo Alto, CA, 94303, USA
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SMN protein promotes membrane compartmentalization of ribosomal protein S6 transcript in human fibroblasts. Sci Rep 2020; 10:19000. [PMID: 33149163 PMCID: PMC7643083 DOI: 10.1038/s41598-020-76174-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 09/24/2020] [Indexed: 12/14/2022] Open
Abstract
Alterations of RNA homeostasis can lead to severe pathological conditions. The Survival of Motor Neuron (SMN) protein, which is reduced in Spinal Muscular Atrophy, impacts critical aspects of the RNA life cycle, such as splicing, trafficking, and translation. Increasing evidence points to a potential role of SMN in ribosome biogenesis. Our previous study revealed that SMN promotes membrane-bound ribosomal proteins (RPs), sustaining activity-dependent local translation. Here, we suggest that plasma membrane domains could be a docking site not only for RPs but also for their encoding transcripts. We have shown that SMN knockdown perturbs subcellular localization as well as translation efficiency of RPS6 mRNA. We have also shown that plasma membrane-enriched fractions from human fibroblasts retain RPS6 transcripts in an SMN-dependent manner. Furthermore, we revealed that SMN traffics with RPS6 mRNA promoting its association with caveolin-1, a key component of membrane dynamics. Overall, these findings further support the SMN-mediated crosstalk between plasma membrane dynamics and translation machinery. Importantly, our study points to a potential role of SMN in the ribosome assembly pathway by selective RPs synthesis/localization in both space and time.
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Vukojicic A, Delestrée N, Fletcher EV, Pagiazitis JG, Sankaranarayanan S, Yednock TA, Barres BA, Mentis GZ. The Classical Complement Pathway Mediates Microglia-Dependent Remodeling of Spinal Motor Circuits during Development and in SMA. Cell Rep 2020; 29:3087-3100.e7. [PMID: 31801075 PMCID: PMC6937140 DOI: 10.1016/j.celrep.2019.11.013] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 09/20/2019] [Accepted: 11/04/2019] [Indexed: 12/19/2022] Open
Abstract
Movement is an essential behavior requiring the assembly and refinement of spinal motor circuits. However, the mechanisms responsible for circuit refinement and synapse maintenance are poorly understood. Similarly, the molecular mechanisms by which gene mutations cause dysfunction and elimination of synapses in neurodegenerative diseases that occur during development are unknown. Here, we demonstrate that the complement protein C1q is required for the refinement of sensory-motor circuits during normal development, as well as for synaptic dysfunction and elimination in spinal muscular atrophy (SMA). C1q tags vulnerable SMA synapses, which triggers activation of the classical complement pathway leading to microglia-mediated elimination. Pharmacological inhibition of C1q or depletion of microglia rescues the number and function of synapses, conferring significant behavioral benefit in SMA mice. Thus, the classical complement pathway plays critical roles in the refinement of developing motor circuits, while its aberrant activation contributes to motor neuron disease.
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Affiliation(s)
- Aleksandra Vukojicic
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Nicolas Delestrée
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - Emily V Fletcher
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | - John G Pagiazitis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA
| | | | - Ted A Yednock
- Annexon Biosciences, 180 Kimball Way, South San Francisco, CA 94080, USA
| | - Ben A Barres
- Department of Neurobiology, Stanford University, Palo Alto, CA, USA
| | - George Z Mentis
- Center for Motor Neuron Biology and Disease, Columbia University, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University, New York, NY 10032, USA; Department of Neurology, Columbia University, New York, NY 10032, USA.
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